I'm giving this one an 'excellent' as well.
When I first heard about this movie, I was pretty excited. Well, it definately lived up to my expectations. It was nice to see a superhero movie where the "hero" isn't necessarily your typical upright do-gooder who stands for truth and justice. I also liked that the world we saw was our own and not stylized in any way. It made the movie feel like a real "what if" scenario. Loved the casting too. Jason Bateman was great as the idealistic PR rep. It's nice to see his career back in full swing. Not that it hasn't been before this movie, I'm just saying. I enjoyed seeing Charlize Theron as well. She was a great mother, wife and fellow superbeing all in one. Finally there's Will Smith. He was believable in the role he played and didn't come off like the star of his own summer blockbuster. This didn't feel like yet another Will Smith vehicle.
As for the story, it didn't have anything I feel like complaining about. For me, everything worked. I can't wait to see where all these negative reviews are coming from. The action was good, I loved the superheroics and I liked that we even got a bit of an origin story. They didn't give us everything, but I didn't feel shortchanged. Some of it is left to the viewer's imagination. I also liked the twist with Charlize Theron's character. I did catch a glimpse of something in one of the trailers several weeks back that suggested that she also had powers, but I couldn't verify what I saw and managed to ignore it. Apparently I pushed it out of my head enough that her having abilities came as quite a surprise. One thing does stand out though. I'm wondering now why she became all sinister and evil-like when she confronted Hancock at his trailer. I think that could have been played better. They also did the bit where the hero starts losing his powers. I was afraid they'd go there, but it was handled quite well and I'm satisfied with what they did. Oh, yeah, I also liked the happy ending with everying being alright with our main characters.
So, there you have it. Can't wait to see what everyone else thinks.