I have to go with the Spider-man; he brought me into the world of comics, is a hero I can relate to most, and I will always had a soft spot for the guy.
Second place is a tie between Power Girl, Machine Man, Rorschach, Deadpool, Hank Pym and Eric O'Grady (both wore Ant Man costumes).
Generally, I like superheroes that somehow stand out from the rest, and have to deal with their weakness (I am more of a Marvel guy)*.
I said that I am more of a marvel guy, but when it comes to teams, I really enjooy DC stuff - unfortunately any of them I pick up and enjoy ends up cancelled: Secret Six (RIP), Doom Patrol (RIP), Metal Men (RIP), Deamon Knights (Hopefully they will last a while), and also Nextwave, from Marvel. God, I love Nextwave! I wish I would have a time to reread it...
About Batman: I just have hard time believing that Bruce Wayne has no superpowers. Come on, he can pull off managing his company, building gadgets, fighting super villains, investigations, being a leader of JLA, fathering Robin, getting multiple college degrees, becoming an expert tactician and martial artist. And people say Batman is one of the most "realistic" heroes. I do not think Bat is any more realistic than Superman or Flash, he is as much of a stretch as those two, but in different aspects. I still like all three of them and do not try to attack any - just saying what are my thoughts on Bat-realism.