First let's assume that Batman: The Dark Knight Rises ends with Bane breaking Batman's back (probably a long shot, but here's hoping).
Now since both Christian Bale and Christopher Nolan have made it clear that this is their last Batman film, the franchise can clearly head in a new direction without any real hang ups.
The best way to do such is to follow the storyline of the Batman comics during the 90's, where after Bane's savage beating of Batman, Wayne leaves the country to receive rehabilitation for his back, but before leaving he turns over the protection of Gotham to Jean-Paul Valley (Azrael) who will fill in as Batman.
This would be ideal because now you can have a few movies without a Bruce Wayne, see a much darker Batman (because let's face it, Jean-Paul has issues), and potentially have a Batman vs Batman beat down in the last film of this series when Wayne returns home to take his rightful spot as Batman.
Plus, and this is huge, the Jean-Paul suit was totally freaking awesome.
Of course this is all just wishful thinking, but come on, it sounds like a good idea. No? Well then how would you continue on the Batman franchise?
P.S. We could just screw it all and fast forward to a Batman Beyond movie, now that would be kick-@$$.