I dig my heroes anti, so Will Smith's Hancock appealed to me the minute I first saw the trailer. A fan of Peter Berg's since Very Bad Things, I expected the dialogue to be tight and the scenes to emphasize the base humanity of the superhero.
In that regard, Hancock didn't disappoint. The dialogue and super-powered gags were the best part of the flick, along with Smith's ability to evolve his character from an unlikable bum to a sympathetic and endearing personality. In addition, Jason Bateman continues to out-do himself in recent flicks; his Ray Embrey may have been the best developed character in the movie.
Much has been made of the plot twist involving Charlize Theron. Although I won't discuss what the twist is here, I will say I thought it was unnecessary, and even detrimental to the film. I understand how the twist was used to explain Hancock's past and powers, but I prefered not knowing. I also preferred Hancock flawed, which he wasn't after the plot twist was uncovered.
Although the movie was entertaining throughout, I thought it's potential was greater than the final product.