Definitely Kasparov, not just because he is more modern, but also Fischer himself said so.
uh...no.
Bobby right up to his death was clowning Kasparov. I would really need to see some strong evidence he said that before I would even consider it might be true.
Here ya go ...
"I object to being called a chess genius because I consider myself to be an all around genius who just happens to play chess, which is rather different. A piece of garbage like Kasparov might be called a chess genius, but he's like an idiot savant. Outside of chess he knows nothing."
Ok sorry I did come off a bit rude. I meant to say that the fact that Kasparov kept playing for a very long time, and even occasionally competes with top GMs today, is extremely impressive. Even if he did "lose to some GMs" or "got beaten to a pulp" in a recent match, it's becuase he plays despite his age. Fischer quit, so that doesn't make him impressive.