Great film and I EAGERLY await to see what happens next.
Ya know its one of these things about the Harvey Dent issue that gets me, despite me "thinking" he was dead I was "sure" he was still alive. I dont know if it was just me but im pretty sure his chest is moving in the "death" scene slightly as if he is still breathing in and out albeit slowly. If you see it again check it out.
It is certainly possible that by managing to cover Gordan's death they have done so with Dents. Again protecting the legacy and allowing Batman to become the "villain" of the piece. Dent had turned into Two Face and was no longer himself, its not like they would have been able to wake him up and be like....."btw all that psychotic stuff that just happened with you, lets forget it and move on"

I am interested to see where it goes.....if it does!
The Joker scenario is an odd one. Obviously by keeping the character alive they would have probably used him in some capacity in future films but since Ledger's sad death this will probably no longer be the case as any other actor would regardless of performance fail in the eyes of the public.
Ledger himself engrossed me in this film and just pulled me in! Fantastic performance and I definitely would not begrudge him a best Supporting Actor Oscar as he certainly wasn't in the film enough to be considered a "lead" that was obviously Bale as Batman.
Though bravo to Ledger his performance was flawless and his character was a different class, certianly the best thing about the film!
And BTW Maggie looks too like Kirsten Dunst for my liking lol!