I personally consider Karpov the 2nd best of all time, after Kasparov. I do think, however, that while Kasparov is/was better, the difference between them is not so great as many people believe. In their 5 matches, they played 144 games, and the score was 73-71 in Kasparov's favor ... so while Kasparov took 4 of the 5 matches, which seems overwhelming, when you actually look at how close each match was, there wasn't that much difference between them (although you can argue that when the chips are down, the player who is able to win when it counts - ie when the match is on the line - time and again as Kasparov did, that player is definitely superior).
I think had Fischer and Karpov played in 1975, Fischer would have won. He was more experienced, and from what I've read, I don't think Karpov had reached his peak. But I think Karpov would've come back in 1978 stronger than before, and would've taken the title. Karpov, as he showed following the loss of his title to Kasparov, wasn't someone to let a disheartening loss crush him. I don't think he would have crumbled, no more to rise, like Spassky or Petrosian before him.
And following what I believe would've been his 1978 victory, I believe he would've been a much stronger player for having played Fischer than he otherwise became. And in 1984 when he met Kasparov, I believe his 5-0 lead would have turned into a 6-0 victory, and Kasparov wouldn't have returned to the scene until 5-6 years later.
So, my thoughts are that he is the second best player of all time. Had he had the opportunity to play Fischer, he would've won the title 3 years later, but been a stronger player overall, and would've retained the title longer, and probably the experience would've given him the edge over Kasparov. Personally, I think Fischer's refusal to play Karpov, and allow him the type of opposition that would've really challenged him in his early years, is the only thing that did keep Karpov from becoming the greatest player of all time.
That's all my own opinion ... you can agree with it or not. As many people have mentioned here, all the discussion regarding the subject is largely speculation.
I do appreciate someone starting the thread though, because although I don't believe Karpov was the greatest ever ... his name is always forgotten in the Kasparov-Fischer debates. And it's nice to finally see someone appreciating how dominant and powerful a player he really was, and including him in the discussion.
Well, let me think, Fischer was a flash in the pan, Kasparov just had good openings, Carlsen just wins because his opponents get tired, Tal just made blunders and his opponents let him mate them, Petrosian just bored his opponents into submission, so it seems Karpov was by far the best.
Allow me to educate you on your chess history.
Karpov....got.....flavored....YOGURT!
So he cannot be considered best.
Now we can consider some other contenders.
Smyslov....won by soviet collusion.
Botvinnik - same.
Euwe....played a drunken Alekhine.
Alekhine played a bored Capablanca.
Capablanca played an over the hill Lasker.
Lasker played an over the hill Steinitz.
Steinitz never played Morphy.
Morphy was the best player ever.
Q.E.D.
lol, nice.