No spoilers from me, so sorry! This was a thoroughly enjoyable, enthralling, exciting movie! Heath Ledger is IMO the BEST Joker I've ever seen (and I'm not just saying that because of recent events!). The character Ledger creates with the Joker is exactly how the Joker should be portrayed (and I'll leave it at that).
Maggie Gyllenhaal was a much better Rachel than Mrs. Cruise, and then of course Christian Bale was terrific once again as Bruce Wayne/Batman.
Some complain that the movie was too long (2 1/2 hours). However, I felt that there was not a single moment when I felt that the movie lulled. To me, the movie should have lasted at least 15-30 minutes longer, just to answer a few questions that I felt were not answered.
But, that's all I will say. I'm sure others will spoil the plot, but I won't. So if you want to know the story line, read someone else's review.
All I have to say is GO SEE THIS MOVIE!!! Men...women..children over 13... You will NOT regret it!