Who's your favorite grandmaster (Post-1920) and why?

Title.

You must have been playing chess for a while. I would love to play against a veteran sometime.

Sincerely, an absolute beginner.

Ben Finegold

Let’s see...Capablanca was after that, right? I love the way he made chess look so easy. His little 2-move combinations make chess seem much easier than it is, and that anyone could be a great player.

Also liked Petrosian and his careful positional crush on people. And those crazy, mysterious moves that don’t seem to do anything, yet he wins anyway.

Magnus Carlsen because he went 2 years without a loss

There were no GM's before 1950 FIDE first awarded the Grandmaster title in 1950 to 27 players. Those players were:

World Champion Mikhail Botvinnik, and those who had qualified for (or been seeded into) the inaugural Candidates Tournament in 1950: Isaac Boleslavsky, Igor Bondarevsky, David Bronstein, Max Euwe, Reuben Fine, Salo Flohr, Paul Keres, Alexander Kotov, Andor Lilienthal, Miguel Najdorf, Samuel Reshevsky, Vasily Smyslov, Gideon Ståhlberg, and László Szabó.

Yeah good point 

Without a doubt Mikhail Tal. His creativity and insane tactical abilities even surpass the great Bobby Fischer for me. Anybody who is being introduced to the game of chess should have seen one of the great wins of Tal to feel the beauty the game is hiding.

For my two penneth it has to be

The late great GM Robert J Fischer for virtually single-handedly defeating Soviet chess dominance and showing chess to the western world. He also invented and gave to chess a modified chess timing system that added a time increment after each move (now a standard practice) and invented the chess variant known today as Chess960. After all of this instead of his country pinning a medal on his chest they forced him into exile and to become a fugitive. Culminating in 2004 when he was arrested and imprisoned in Japan because the US government had revoked his passport. Eventually, he was given Icelandic citizenship and passport which allowed him to live in Iceland until his death in 2008.

Shame on you America, God bless Iceland and RIP Bobby.

Rashid Gibiatovich Nezhmetdinov. An extremely tactical and creative attacking player who was close friends with Mikhail Tal. This guy even defeated Tal and many other contemporaries of his day, but yet was never given a GM title for political reasons, as far as I know. Very entertaining games.

Hard for me to say someone other than Fischer (as an American). But so many great players. I currently like Grischuk for many things but especially his propensity for time trouble, devil-may-care attitude, and Russian fatalism. Dubov is also up there.

I go for Sultan Khan. Never awarded a GM title but his story is incredible. Comes to Britain as a servant, doesn't speak English, can't read or write, only learnt Western chess at 21, doesn't know Western notation, knows little to no opening theory, yet wins the British championship 3 times and stands toe to toe with the best players in the world for 5 years before returning to British India with his master never to grace the board again. Capablanca described him as a genius. 

Who's your favorite grandmaster...

IM Rashid Nezhmetdinov and the untitled Sultan Khan do not qualify.

Semyon Furman:

On one occasion, again in Zelenogorsk, while the adults were sitting at
the card table, Furman's little son Sasha and Irina Levitina decided to try
out an inflatable dinghy. The wind got up and began carrying it away from
the bank. When the situation became alarming, everyone grew anxious:
'They are already a long way off, we must do something.' 'Until this rub-
ber is completed', said Furman, 'no one is going anywhere.'

Nuff said.

I agree