Here's one I think no one has suggested:
Gotham's Soul
I think (from Nolan's comments about ending the storyline set up from BB) this is the theme that this movie will really come down to and I like that as a title too. It's a reference to Joker's line in TDK about "the battle for Gotham's soul" and how he wouldn't risk it through a personal conflict with Batman but by corrupting other freaks like Two-Face and (presumably) the antagonists of the third film. Ultimately, like Batman Begins and The Dark Knight title cards ended up being about the ending of those respective movies, this one would be about Bruce's victory in his quest and the conclusion of the trilogy. It can also be interchangable as a reference to "Batman" like the last two films (if people are anal about that), because the Batman can symbolically be seen as Gotham's Soul (the proponent motivating them to save their own city). In all, I think it's a perfect fit, maybe not for marketing but the film itself, but Nolan will probably come up with something different.