Kick Ass mostly because he's completely worthless and it was a little interesting to see the concept of how a real teenager trying to be a super hero would be, the fact that he just won't give up even though he's worthless makes him pretty likeable, it's also funny to realize that most people that have fantasized about being super heroes would be pretty much as useful as Kick Ass, though to be fair what I like about him is the concept since I don't really remember the movie all that well, my memory kinda sucks, so it's possible that in the movie he sucked or the other characters were better, still the concept of Kick Ass is pretty interesting, though I heard that Bigdaddy wasn't good in the comic and something about stealing Hit Girl from his wife because he was bored or something and then he trained her to be a super hero for those reasons or something, if it's like that then Bigdaddy is definitely the more interesting concept out of all of them.