Too hard to choose.
Conroy is fantastic, but he delivered the voice (a great one at that), the rest was up to the animators. Combined, I think they make the ideal Batman, atleast my ideal Batman but it's not really fair to compare BTAS Batman to the live action versions.
The film actors had to portray Batman/Bruce Wayne with vocals, looks, in the Bat-suit, as Bruce Wayne, and other acting ranges for the on screen character.
So for me, Conroy, or more importantly "BTAS" Batman is in a league of it's own. My favorite "Batman" but in non-live action form.
For me, it's a toss up between Christian Bale and Michael Keaton. I should note however I prefer their FIRST performances as Batman. Bale in
Begins and Keaton in
Batman.
Bale in
TDK annoys me and there are only a few parts where I enjoy Keaton as Batman in
Returns. It's like both actors were either trying too hard or were bored. That along with Bale's ridiculous nasal growls and Keaton's ____ faced grin after strapping a bomb to a thug make me root for the villians, Ledger Joker, Penguin and Catwoman even more.
Christian Bale is fantastic as Bruce Wayne/Batman in
Begins, I thought he was the perfect choice to portray the character in '04/'05. We were shown Batman, two versions of Wayne, and he had a wide range of other likeable traits as Batman. It felt like we were along for his journey in becoming Batman, following him in the prison camps, to flashbacks as a child, to the training to become Batman. The film was a great origin story/Batman movie
because of Bruce Wayne and we knew more of him than the previous films.
Michael Keaton portrayed a neurotic, anti-social Batman. Really mysterious and full of angst. As Bruce Wayne, he kind of had a childish, Clark Kent thing going on, like he COULDN'T or didn't want to be Bruce Wayne. He preferred being Batman and his attitude completely changed. Surveying the city in front of dozens of monitors, having a hard nosed, no nonsense look on life. It was great. He was essentially THE Batman throughout the film, with "Bruce Wayne" being the mask.
Conroy is king because I love BTAS and Keaton and Bale are interchangeable depending on what type of Batman/Bruce Wayne I want to see.