Right now, in the flush of enjoyment, I'm half ready to call Hancock the best superhero movie around... or at least the best modern superhero movie.
It doesn't take forever to get into the story. It means for the hero to come across as an unlikable asshole at times so that he can grow as a character. And it uses its main female character in a much more effective and feminist way than Spider-Man, Batman Begins and the recent Superman combined.
It has an interesting story that takes several unexpected twists that took my breath away when revealed but made complete sense. The character development is wonderful for all of the main characters. The most rewarding part, however, is the complex relationship dynamic between the three main characters.
Plus, it has Will Smith (who is just awesome) doing his best acting job yet, Jason Bateman (who played the hilarious and brilliant 'relatively' normal character of Michael Bluth in Arrested Development) being a strong grounding force, and Charlize Theron as a powerful, likable, and complicated female character.
It's not your typical superhero movie. And that's what makes it so good.
*vague spoilers in comments*