Personally, I don't like Bale as Batman or Bruce Wayne. I don't get the appeal.
Keaton was great, Kilmer was ok. Clooney might have been great, but the film was so bad it's hard to see how. (Chris O'Donnell was pretty good as Robin in both films.)
I agree that Conroy's voice defines Batman as a character, but he wouldn't work onscreen. So that eliminates him.
Considering all that, I still have to go with Kevin Porter as the best onscreen Batman I've ever seen. Check out City of Scars.
The writing is just ok, and some of the acting is barely passable, but Porter IS Batman.
(FYI, I'm not affiliated in any way with Bat In The Sun Productions. Just a fan.)