Just when you think Nolan couldn't make the plot anymore complicated - it gets more complicated. The story was wonderfully written and delivered with stellar performances from Oldman, Ledger, Freeman, Gylenhal(sp?), Eikhart(sp?) and Bale. Dark Knight keeps you intrigued in it's multi-faceted characters; truely forcing the audience to understand and, to an extent, accept the morale questions posed by the movie's themes. You see the quandaries each character is confronted with and the difficult decisions they make. It makes you question your own standards of right and wrong.
A true pychological blast. And all the awesome pyrotechnics and action doesn't hurt either!