The main thing about this movie is that Heath Ledger was awesome. It doesn't happen very often, but if I wouldn't have know that was Heath Ledger, I wouldn't have known it was Heath Ledger. I cannot fathom how his performance wouldn't be Oscar-worthy, although it appears that the Academy is somewhat unwilling to nominate dead people for awards. I very honestly think that his performance was as good as Charlize Theron's in "Monster". In fact, in some ways, I think Ledger's performance was better because Charlize Theron had the benefit of having an actual person to base her performance on. The Joker, as you may or may not know, isn't real.
Christian Bale makes a pretty good Batman, to include the relatively stupid Batman voice. This was brought up in conversation today, and the fact is that the gravelly voice that sounds a bit fake is accurate to the comics. I mean, Batman can't sound like Bruce Wayne, right? Anyway, aside from the voice, Bale is able to come across as intense, and that's good.
The way that the Harvey Dent issue was handled was good, and unexpected. Gary Oldman rules as Commissioner Gordon, and Maggie Gyllenhall is adequate. I am not a big Maggie Gyllenhall fan, so I am a little biased.
Anyway, if you like superhero movies, this is a pretty good one, and is arguably the best of the bunch, thanks to the fact that there is some real drama mixed in with, you know, a guy dressed as a bat. I found Iron Man to be more entertaining, but The Dark Knight is probably more compelling. In any event, you should see it.