Loved it. I think Heath Ledger did a fantastic job. But I still prefer Jack Nicholson in that role. Nobody...just nobody can do 'that' smile better than Nicholson! And oh...that wicked look paired with that laugh....it got me hooked me right from the beginning.
Christian Bale still looked just as good as he had always, but well, I think he fares better in roles like The Machinist and American Psycho.
Anyway, the only reason why I wanted to watch this movie was because I'm quite a fan of Heath Ledger and Christian Bale ;) (dear, please don't kill me hahahaha =P)
But overall, this is a great movie. Go watch it!