I must say TDK felt a bit anticlimactic, and a bit too long for me.
Heath Ledger is amazing, all the hype surrounding his performance IS justified, untimely death or not, I went from finding him hilarious to unsettlingly disturbing almost in a heartbeat at times, but one performance can't propell a whole film to brilliance, it can only lift it a notch above disappointing IMO.
The film's final 20 minutes felt the wrong way round to me, and too many of the main characters' plot resolutions were completely unsatisfying, I think I was supposed to be left hankering for a sequel, but I wasn't I'm afraid.
What I did like about it was, compared with so many other comic-book-based films, it's not a CGI-porn-fest, it's a proper dark action flick (Nolan really is a master of his craft), and the use of CGI is nice and organic looking when it is there.
TDK is far better than any of the three Spiderman films, certainly better than Ironman (but completely different, it's hard to directly compare the two), but I'm not sure that it comes close to topping Batman Begins, Hellboy or Sin City, my personal favourite comic book movies.
I would still give it 4/5, but that score's raised by about 1 by Ledger's Joker.
Given another viewing I may enjoy it more, especially as last night's screening was hotter and stickier than me being locked in a greenhouse for 12 hours with Pamela Anderson.