Okay, now I've seen this masterpiece twice, and it's making much more sense. Seeing the Joker cast as a sadistic, malevolent force, rather than just a mere super villain, has finally given me someone (bad) to look up to! It really is how he said it to the mobster: "Gotham needs a better class of villain, and I'm gonna give it to 'em!"
The action was great. The actors were near flawless (with Ledger being completely flawless), and the sound and music was highly praiseworthy. The Dark Knight is certainly the best movie of the year, and perhaps the best superhero movie ever (if I can ever push the original Spiderman out of my mind).
One question: Did the Joker lie to Batman to get him to go save Harvey, knowing that Batman would reflexively go after Rachael instead?