Bleh, I'll join the chorus of those not caring for the title. Bland and cheesy, IMO. Yeah, it gets the theme of the movie across and it works, but if feels cheap, or at least pedestrian. "Rise of the Dark Knight" would work better, IMO. If you absolutely have to have The Dark Knight in there (and you're not willing to use The Dark Knight Returns, which is the best name for the theme I assume Nolan's going for), how about The Dark Knight Triumphant? (The) Dark Knight Victorious? If he's not going to be publicly accepted till the end, how about Knightfall?
But these are quibbles; "Batman Begins" is no great shakes either, and it's certainly not "Attack of the Clones."
The Riddler would've been fun, but it'll be interesting to see who else Nolan brings in. What are the chances do you think this one will have a female character that is both significant to the plot and survives? Or maybe even more than one significant, just for kicks?