Not even close, Bale all the way.
Bale pulled off Batman for 3 movies, tracking the evolution of the character
- his rise, fall, and eventual ending.
I think the growl was a bit OTT in TDK and TDKR, but otherwise, Bale was great at embodying those qualities that define Batman - obsession and rage.
Now the character was written well, but Bale has the acting chops to pull it off ( if you don't believe me, watch American Psycho, or The Fighter).
Bale played 3 discrete characters, Bruce Wayne the public face, the real Bruce Wayne underneath, and Batman. For a long time I thought it was lame that Bale spoke in his Batman voice to people who knew his secret
(e.g. when he tells Rachel "They're coming" in TDK and to Selina in TDKR)
but then I realised that it was because when he switches into Bat-mode, he is a different person entirely - it was clearly an acting/directing choice, rather than an oversight.
Some people think Chris Evans is a better Cap, than Bale was Batman - but Evans is only playing one character, and a pretty 2 dimensional one at that ( apologies to Cap fans, but Cap is a pretty boring character, kicks a lot of ass but still kind of boring). Bale is playing a couple of different roles.
I give big props to Keaton for making Batman legit again on the big screen, and playing against type. A job well done.
But Bale inhabited the role in a way nobody has. He managed to share the scene with Ledger's Joker, and not be completely eclipsed (by what is probably the best performance in a comic book movie ever), in the interrogation scene Bale holds his own (also probably the greatest superhero - villain scene ever).
Anyway, that's how I see it, and Affleck will have to be absolutely amazing to come close to Bale's performance.
All this is just IMO, and I respect everyone else's opinions (even those who liked George Clooney as Batman).
cheers.