One first impression - AWESOME!!
Christopher Nolan returns with a superb sequel to what was an interesting (& most required) restart to the Batman franchise. Teaming up with his brother, he delivers a dark and brooding story, which keeps the audience engaged thru' out.
Batman keeps doing good for Gotham, but not everyone perceives him to be a hero... meanwhile a while knight is emerging, DA Harvey Dent who seems to have the best interests of Gotham (and Rachel!!) at heart. This seems to be the perfect setup required for Bruce - let Dent take care of the criminals and end his taxing double-life as Batman...
....until of course The Joker turns up ; a man with no morals and a sheer mission to give the people a "better class of criminal", he shows Gotham how terrorizing a person can be, holding an entire city hostage to his antics.. brilliant!!
I wont discuss the story any further becoz it would be "spoiler-time", but suffice to say it packs in a lot of bang with dark themes and moral dilemmas, every major character has a part to play and is left to question their basic ideals..
Performances are all top notch with Christian Bale and Heath Ledger deserving special mention.. It is indeed a great achievement that Nolan managed to get this much of a good screenplay into what is essential a comic-book summer blockbuster without compromising on the big-setpiece action sequences...
My only real grouse is the ending (which I dont want to reveal) and also possibly using Two-Face pretty lamely (though his story arc lends a lot credence to the Batman-Joker rivalry)..
All said and done - a real gem and possibly the best comic book movie ever (possibly, only because I havent seen all the comic book movies)...
Edit : This came about during discussions on Muhi's reply - Now that Ledger is dead (but the Joker isnt) (spoiler in white), I am really interested to see what Nolan does with part 3. "The Dark Knight" is going to be very very difficult to live upto!!
Edit 2 : I am notching up the score by 2 more points after watching the movie again. Given the way the story goes, the ending is really very well done. Its just that when I was watching the first time, Nolan was setting the bar higher with every sequence and I expected a "bang" at the end. Of course, one question remains : How & when did the Joker rig up the bombs on the yachts, without anyone noticing? Fans have already answered on imdb saying he used the 1 year period from part1 to do this, but while this can explain everything else, it doesn't explain the yachts. (spoiler in white)
Score : 84 (DONT MISS IT!!)