I woulda picked Iron Man, but after seeing the Avengers they are all awesome. I mean, Thor is a god, so I guess I gotta go with him. Though, from the Avengers the Hulk is a Bad Ass and Captain America was way better than in his movie. Hawkeye and Black Widow... not so much.
Deadpool is the greatest of all the superheros, mainly because he knows that he is not real.