Just to be off-topic to start things off:
@Girl Gamer Elite: About 300, I think you're right, people thought it was amazing because of the art design, action and what not, I didn't think it was good at all to be honest. Totally overrated.
Anyway, I watched this movie on the opening day early session.
I thought it was a great movie and one of the best (if not the best) superhero movies I've ever seen and that feeling hasn't changed.
BUT what I do see now, is that for me what really brought this movie to the next level was heath ledger, one of the best performances I've seen in a while.
What kind of sucks for the movie though is that most will overhype it because of heath ledger's death (no disrespect to the person intended) and will look past his performance (if you've seen any of his other films, the transformation is quite astonishing to say the least), focusing more on his death, which is quite sad. The overhype will consequently bring people who a) actually didn't like the movie (i.e die-hard DC fans that point out every deviance from the comics) or b) the people that hate for the sake of hating on something.
Now onto the film itself: Like I said, one of the better movies I've seen. Truly a great cast (as was from batman begins) and the plot was awesome in the way it played out and it's content. I especially liked the bit when gotham showed signs of humanity when the two boats chose not to blow each other up for self-preservation (reminded me of the bit from spiderman 1 where the citizens were throwing crap at the green goblin for heckling spidey when he was trying to save the bus full of kids, I'm a sucker for those sorts of moments).
I also liked the fact that it didn't follow the super hero movie trend of letting iconic villains die. Batman doesn't kill, and that's the way it should stay.
My only issue with the film was Two Face. I thought his transformation was great, but a little rushed and I would have liked him to have more time to cross over.
About the villain in the next film:
I'm going to say either Talia ah gul, Riddler or Two-Face.
Talia really because it makes a nice round circle with the first film.
Riddler because it can keep the film in the real world feel that the first 2 films had. I would also be interested to see Nolan's take, because I would say that it'll feel more like the riddler then a knock-off joker.
Two-face, well I don't think dent died in the second film. Most obvious point is batman doesn't kill. Second one is that no one (batman or gordon) explicitly says he's dead during that scene. Third, the public funeral could easily be put as a front for moving harvey dent into arkum. Gordon apparently died in the movie and he was still alive.
This sort of played out well in that had we known for sure that harvey dent did die in this film and with the sad death of heath ledger (the joker cannot be recasted without a huge backlash), there would be no tie-in's in the new batman film with the previous film (i.e Scarecrow in the first bit of TDK).
I think Two Face with Talia (seeking revenge for her father) would be a good combination as they both can blame batman for the loss of a loved one.
About robin: I think robin should be introduced at the end of the 3rd movie as a kid (I thought that little blonde haired kid in batman begins would become robin at the end of that film or show signs of that). It might not tie in with the comic book origins of robin (I'm not familiar with it) but robin has to appear in the third film, he's too important to the batman story to be entirely excluded.
I would say having him at the end of the film as a kid is the best bet because a) it includes robin in the batman films and b) it doesn't force the ridiculous robin costume (which can either be classic red on green which'll look terrible on the big screen and dark setting of gotham OR it can be like batman and robin and be burned by DC fans for deviating too much from the original).
Sorry for the huge text.