Louis Eichborn may well be the most overrated player in history.
There are some (including those at Microsoft True Skill) that rate Eichborn as better than Morphy, Steinitz, Lasker, Capa, Alekhine, Euwe, Botvinnik, Smyslov, Tal, Petrosian, Spassky or anyone until Fischer.
http://research.microsoft.com/pubs/74417/NIPS2007_0931.pdf
The most underrated is Botvinnik.
Overrated in my opinion was Kasparov.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
The absurdity of that statement ...
Neither one are the greatest of all time.
The disparity between Carlsen and Kasparov is just rating inflation. You can admit this inflation exist and Kasparov is maybe number 1. You can deny it and he is at worst number 2.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
As a classical player, Nakamura is seriously underated. Nakamura made huge contributions to the wayward queen attack and is also the best classical calculator in all of chess history, the two reasons why Nakamura isn't world champion is because his positional and tactical understanding isn't on the level of world champion players.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
As a classical player, Nakamura is seriously underated. Nakamura made huge contributions to the wayward queen attack and is also the best classical calculator in all of chess history, the two reasons why Nakamura isn't world champion is because his positional and tactical understanding isn't on the level of world champion players.
Best calculator? Hell no. He isn't even top 5. That is ridiculous.
Tal, Morphy, Capablanca, Fischer, Karpov, Kasparov and Anand were all definitely better at calculating than Naka nobody.
Underrated surely is a guy named N.N. he beated nearly all worldchamps in history and he never get an Elo-Rating 
Underrated surely is a guy named N.N. he beated nearly all worldchamps in history and he never get an Elo-Rating
He beat all of them but Tal
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
As a classical player, Nakamura is seriously underated. Nakamura made huge contributions to the wayward queen attack and is also the best classical calculator in all of chess history, the two reasons why Nakamura isn't world champion is because his positional and tactical understanding isn't on the level of world champion players.
Best calculator? Hell no. He isn't even top 5. That is ridiculous.
Tal, Morphy, Capablanca, Fischer, Karpov, Kasparov and Anand were all definitely better at calculating than Naka nobody.
Calling someone ridiculous because they have a different opinion means you simply suck at arguments.
Tal was only good at calculating as far as sacrifices were involved.
Morphy was playing during the 1800's, he wasn't anywhere near the level of a super GM.
Capablanca wasn't a particularly good calculator, he understood the tactical and positional elements required for simplification, as well as occasionally having a good tactical grasp as in his game against Frank Marshall.
Fischer wasn't a good calculator. he just had a very good grasp of pawn structures, positional harmony, as well as a great grasp on creating attacking chances as well as having a very deep grasp on all the tactical and positional elements within his narrow repertoire.
Karpov was mostly a positional player, although once he was in superior position to his opponents, he was fairly good at calculating the consequences once he set up an attack, although he wasn't as good a calculator as Nakamura.
Kasparov was a decent calculator, although he placed a greater emphasis on dynamism more than anything else.
Anand is only good at knowing how to mobilise and coordinate the knights, as well as knowing how to increase their activity, other than that his area of knowledge was in counter-play.
Carlsen is a good calculator too, but I think Nakamura is far better at calculation.
Being good at chess isn't just about calculation, Nakamura's style just happens to be the most calculation heavy.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
As a classical player, Nakamura is seriously underated. Nakamura made huge contributions to the wayward queen attack and is also the best classical calculator in all of chess history, the two reasons why Nakamura isn't world champion is because his positional and tactical understanding isn't on the level of world champion players.
Best calculator? Hell no. He isn't even top 5. That is ridiculous.
Tal, Morphy, Capablanca, Fischer, Karpov, Kasparov and Anand were all definitely better at calculating than Naka nobody.
Calling someone ridiculous because they have a different opinion means you simply suck at arguments.
Tal was only good at calculating as far as sacrifices were involved.
Morphy was playing during the 1800's, he wasn't anywhere near the level of a super GM.
Capablanca wasn't a particularly good calculator, he understood the tactical and positional elements required for simplification, as well as occasionally having a good tactical grasp as in his game against Frank Marshall.
Fischer wasn't a good calculator. he just had a very good grasp of pawn structures, positional harmony, as well as a great grasp on creating attacking chances as well as having a very deep grasp on all the tactical and positional elements within his narrow repertoire.
Karpov was mostly a positional player, although once he was in superior position to his opponents, he was fairly good at calculating the consequences once he set up an attack, although he wasn't as good a calculator as Nakamura.
Kasparov was a decent calculator, although he placed a greater emphasis on dynamism more than anything else.
Anand is only good at knowing how to mobilise and coordinate the knights, as well as knowing how to increase their activity, other than that his area of knowledge was in counter-play.
Carlsen is a good calculator too, but I think Nakamura is far better at calculation.
Being good at chess isn't just about calculation, Nakamura's style just happens to be the most calculation heavy.
I didn't call anyone ridiculous. What I said is "That is ridiculous."
Opinions are not opinions if they are factually wrong.
You're making a lot of assertions (all incorrect) for someone with a three digit rating.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
As a classical player, Nakamura is seriously underated. Nakamura made huge contributions to the wayward queen attack and is also the best classical calculator in all of chess history, the two reasons why Nakamura isn't world champion is because his positional and tactical understanding isn't on the level of world champion players.
Best calculator? Hell no. He isn't even top 5. That is ridiculous.
Tal, Morphy, Capablanca, Fischer, Karpov, Kasparov and Anand were all definitely better at calculating than Naka nobody.
Calling someone ridiculous because they have a different opinion means you simply suck at arguments.
Tal was only good at calculating as far as sacrifices were involved.
Morphy was playing during the 1800's, he wasn't anywhere near the level of a super GM.
Capablanca wasn't a particularly good calculator, he understood the tactical and positional elements required for simplification, as well as occasionally having a good tactical grasp as in his game against Frank Marshall.
Fischer wasn't a good calculator. he just had a very good grasp of pawn structures, positional harmony, as well as a great grasp on creating attacking chances as well as having a very deep grasp on all the tactical and positional elements within his narrow repertoire.
Karpov was mostly a positional player, although once he was in superior position to his opponents, he was fairly good at calculating the consequences once he set up an attack, although he wasn't as good a calculator as Nakamura.
Kasparov was a decent calculator, although he placed a greater emphasis on dynamism more than anything else.
Anand is only good at knowing how to mobilise and coordinate the knights, as well as knowing how to increase their activity, other than that his area of knowledge was in counter-play.
Carlsen is a good calculator too, but I think Nakamura is far better at calculation.
Being good at chess isn't just about calculation, Nakamura's style just happens to be the most calculation heavy.
I didn't call anyone ridiculous. What I said is "That is ridiculous."
Opinions are not opinions if they are factually wrong.
You're making a lot of assertions (all incorrect) for someone with a three digit rating.
That kid probably watched Hikaru draw some arrows on stream and thought, "This guy's the best 'calculator' in the world!" 
My candidate for most underrated GM of all time is Efim Geller. He had a career plus score against 4 world champions -- Botvinnik, Fischer, Petrosian, and Smyslov -- and an even score against Tal. He was one of the pioneers of the KID and contributed a lot to the theory of the Sicilian. In the late 1960s, Botvinnik considered Geller to be the strongest player in the world.
My candidate for most underrated GM of all time is Efim Geller. He had a career plus score against 4 world champions -- Botvinnik, Fischer, Petrosian, and Smyslov -- and an even score against Tal. He was one of the pioneers of the KID and contributed a lot to the theory of the Sicilian. In the late 1960s, Botvinnik considered Geller to be the strongest player in the world.
Fine also had a cumulative plus score against the world chess champions which he played against ...
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
I wanted to write that "this comment really did not age well", but then I realize that this comment was written just yesterday, when Caruana is number 5 in the world. Bizarre.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
As a classical player, Nakamura is seriously underated. Nakamura made huge contributions to the wayward queen attack and is also the best classical calculator in all of chess history, the two reasons why Nakamura isn't world champion is because his positional and tactical understanding isn't on the level of world champion players.
Best calculator? Hell no. He isn't even top 5. That is ridiculous.
Tal, Morphy, Capablanca, Fischer, Karpov, Kasparov and Anand were all definitely better at calculating than Naka nobody.
Calling someone ridiculous because they have a different opinion means you simply suck at arguments.
Tal was only good at calculating as far as sacrifices were involved.
Morphy was playing during the 1800's, he wasn't anywhere near the level of a super GM.
Capablanca wasn't a particularly good calculator, he understood the tactical and positional elements required for simplification, as well as occasionally having a good tactical grasp as in his game against Frank Marshall.
Fischer wasn't a good calculator. he just had a very good grasp of pawn structures, positional harmony, as well as a great grasp on creating attacking chances as well as having a very deep grasp on all the tactical and positional elements within his narrow repertoire.
Karpov was mostly a positional player, although once he was in superior position to his opponents, he was fairly good at calculating the consequences once he set up an attack, although he wasn't as good a calculator as Nakamura.
Kasparov was a decent calculator, although he placed a greater emphasis on dynamism more than anything else.
Anand is only good at knowing how to mobilise and coordinate the knights, as well as knowing how to increase their activity, other than that his area of knowledge was in counter-play.
Carlsen is a good calculator too, but I think Nakamura is far better at calculation.
Being good at chess isn't just about calculation, Nakamura's style just happens to be the most calculation heavy.
I didn't call anyone ridiculous. What I said is "That is ridiculous."
Opinions are not opinions if they are factually wrong.
You're making a lot of assertions (all incorrect) for someone with a three digit rating.
You're an idiot, you can't come up with a retort so you show yourself to be an idiot.
Overrated: Nakamura
Underrated: Caruana
A lot of people forget that Fabiano Caruana would be literally the greatest chess player of all time if Magnus didn't exist.
As a classical player, Nakamura is seriously underated. Nakamura made huge contributions to the wayward queen attack and is also the best classical calculator in all of chess history, the two reasons why Nakamura isn't world champion is because his positional and tactical understanding isn't on the level of world champion players.
Best calculator? Hell no. He isn't even top 5. That is ridiculous.
Tal, Morphy, Capablanca, Fischer, Karpov, Kasparov and Anand were all definitely better at calculating than Naka nobody.
Calling someone ridiculous because they have a different opinion means you simply suck at arguments.
Tal was only good at calculating as far as sacrifices were involved.
Morphy was playing during the 1800's, he wasn't anywhere near the level of a super GM.
Capablanca wasn't a particularly good calculator, he understood the tactical and positional elements required for simplification, as well as occasionally having a good tactical grasp as in his game against Frank Marshall.
Fischer wasn't a good calculator. he just had a very good grasp of pawn structures, positional harmony, as well as a great grasp on creating attacking chances as well as having a very deep grasp on all the tactical and positional elements within his narrow repertoire.
Karpov was mostly a positional player, although once he was in superior position to his opponents, he was fairly good at calculating the consequences once he set up an attack, although he wasn't as good a calculator as Nakamura.
Kasparov was a decent calculator, although he placed a greater emphasis on dynamism more than anything else.
Anand is only good at knowing how to mobilise and coordinate the knights, as well as knowing how to increase their activity, other than that his area of knowledge was in counter-play.
Carlsen is a good calculator too, but I think Nakamura is far better at calculation.
Being good at chess isn't just about calculation, Nakamura's style just happens to be the most calculation heavy.
I didn't call anyone ridiculous. What I said is "That is ridiculous."
Opinions are not opinions if they are factually wrong.
You're making a lot of assertions (all incorrect) for someone with a three digit rating.
That kid probably watched Hikaru draw some arrows on stream and thought, "This guy's the best 'calculator' in the world!"
I don't go through silly videos these grandmasters make to try to gain money. Another accusation.
My candidate for most underrated GM of all time is Efim Geller. He had a career plus score against 4 world champions -- Botvinnik, Fischer, Petrosian, and Smyslov -- and an even score against Tal. He was one of the pioneers of the KID and contributed a lot to the theory of the Sicilian. In the late 1960s, Botvinnik considered Geller to be the strongest player in the world.
Fine also had a cumulative plus score against the world chess champions which he played against ...
Reuben Fine has never had a plus score against any world champion, you are completely wrong, dimwit.
My candidate for most underrated GM of all time is Efim Geller. He had a career plus score against 4 world champions -- Botvinnik, Fischer, Petrosian, and Smyslov -- and an even score against Tal. He was one of the pioneers of the KID and contributed a lot to the theory of the Sicilian. In the late 1960s, Botvinnik considered Geller to be the strongest player in the world.
Fine also had a cumulative plus score against the world chess champions which he played against ...
So by this argument you decide to downplay both Keres and Korchnoi, shut up, pushing your weight around like some loser, you are no doubt not as brash in person.
Fine also had a cumulative plus score against the world chess champions which he played against ...
Reuben Fine has never had a plus score against any world champion, you are completely wrong, dimwit.
Actually, @Justs99171 is correct. Fine had lifetime plus scores against Lasker, Alekhine and Botvinnik and had an even score against Capablanca and Euwe.
Bronstein underrated
Overrated? Hmmmm not sure. :)