anand because he aborted the vote chess game...
Biggest ego -- Carlsen, Anand, Kramnik?
Anand.
I can't remember the exact quote, but there was one I read a while ago by him that made him come off as a bit of a douche.
To me Anand seems to be one of the most humble of all World Champions and top players, while Kramnik frequently has come around as quite pompous. When he recently stated that Carlsen's lead over everyone else on the rating list had nothing to do with chess, and that he in fact was no better than Kramnik himself or Aronian, it wasn't the first time he said that type of thing.
I think Anand is the least egotistical and Carlsen is the most.
You need to see his games. He makes a smile often when the opponent makes a move, even if the opponent is 2800+ like Kramnik. doesn't matter he wins in the end through a rook sac. Also, sometimes, he looks bored which is highly egotistical. Also, when he is paired up against a woman, he looks obviously annoyed. Judith Polgar was really embarassed when he was looking here and there looking annoyed.
I can't put my finger on it, but for some reason my perception is that Kramnik and Anand are both very egotistical. I'm sure Carlsen has flashes of ego as well (as we all do) but he seems less egotistical. I think maybe it's based on watching their post-game comments. Am I way off base?