John Constantine
I remember when I saw Ed Wood for the first time, I was unintentionally giggling my head off when he meets Orson Welles, because it was Maurice LaMarche doing the voice! It was Brain's voice coming out of some guy's mouth! whee I thought that was frikkin' hilarious that they did that though not too surprising given that LaMarche has made a career out of impersonating Orson Welles. That's at least the third time I've seen him impresonate Welles in something.
It would probably blow your mind John that Kenny was also the voice of Heffer on Rocko's Modern Life.
Also John if you've never seen Mr. Show, I guarantee once you see it that you will think of Tom Kenny in an entirely different light. I can't watch Mumbo Jumbo without thinking of Professor Ellis D. Trails (say that out loud and you should get the joke) from the "Altered State of Drugachusettes" skit. Hell I can't listen to Kenny's voice and not think of half the skits he was in on that show.
If you ask me sometimes it's fine to use the same actor for multiple roles. The Simpsons has essentially 6 VAs; Dan Castellaneta, Julie Kavner, Nancy Cartwright, Yeardly Smith, Harry Shearer, and Hank Azaria. Those 6 voices with a few exceptions pretty much do the entire cast and have done them pretty damn well since 1989. As mentioned earlier Billy West and John DiMaggio are pretty much at least half the cast of Futurama. Billy West's impersonation of Phil Hartman (who was the original choice to play Zap Brannigan!) for Zap Brannigan is so dead on yet at the same time this is the guy who also played (courtesy of imdb)
- Doug and Roger
- Both Ren (after John K. left) and Stimpy (heck from I can see most of the cast of Ren and Stimpy)
- the most recent voice of Popeye, Bugs Bunny, and Porky Pig
- Zoidberg! (which surprised the hell out of me!)
Amd countless others. It obvious that some folks are in the same league as Mel Blank. However in alot of anime dub VAs are just terrible and they get used over and over again. ADV's in house production unit is absolutely atrocious the majority of the time (though I liked the dubs for RahXephon and Gasaraki). The dub for Neon Genesis Evangelion makes my skin crawl everytime I have to hear it. It really depends on the talent to be honest.