Bale.
Keaton is so far my number 2 but that's only because everyone else was just horrible (in my opinion, of course). Keaton was enjoyable, as always as an actor. But he wasn't very Batman or Bruce Wayne for me. It felt like an experiment to have Bruce be a guy who isn't very built, wears glasses, like Spider-Man seems generally weak but feels more intimidating when he puts the suit on, ignores Gordon, and kills criminals left and right.
Entertaining performance but not my Batman. Looked great in the cowl though.
So Bale wins that round for Bat-characterization. As an actor he also wins while in the suit, even though some enjoy the calmer Keaton. I prefer Bale channeling a demon's shadow side AND rage as a form of therapy for himself...but to scare off criminals as well. Batman represents Bruce Waynes dark side, who he truly is, he's like a demon who's constantly talking himself into pulling back. He can't speak like he does normally because that would give away his identity (Conroy's voice is gold but that approach doesn't work when you try to make it believable). But at the same time he's not deepening the voice just to throw people off, it's his anguish seeping through the suit. All the years of pain built up, finally being released via the Batman because he can't release it in a board meeting or towards Alfred.
Bale understood that. It's not everybodys favorite take but it made the most sense to me. Plus Christian is my favorite actor out of that entire list.