Okay, with voice actors, it's a bit different. There are voice actors that fit particular eras of characters better than most. For example, yean, duh. Conroy is the be-all end-all voice of Batman. He's who I hear whenever I read the comics, his voice is what I draw on to write Bruce's dialogue, both inner and outer.

However. I don't particularly hear his voice when reading comics of an older era. The 70's and every era before that have their own Batman that isn't Conroy, for me. So with that said...

1939's Batman - Jeremy Sisto
1940's Batman - Gary Owens
1950's Batman - Diedrich Bader
1960's Batman - Adam West (he voiced Batman several times too)
1970's Batman - Bruce Greenwood
1980's Batman, onward - Kevin Conroy
Possible Future Batman - Michael Ironside

Shout-outs to Roger Craig Smith, Will Fredile, Olan Soule, and Peter Weller for being great in their own right. If I had to choose a voice that wasn't Conroy for UOU Batman specifically, I'd actually use either Smith or Fredile. I actually wouldn't mind Fredile playing Batman proper, given his Terry McGinnis is essentially a Year One era Batman mixed with Dick Grayson.