[AladdinsGenie]

Jim Cummings and David Odgen Stiers could pretty much play every character in the history of ever if they tried

[APK]

I don't think I have any favorites, but I love Eric Stuart, too

[DLN001]

I treat voice actors like any regular celebrity (their even treated like that in Japan), and there are several that I love so much. Here's a couple of my favorites off the top of my head with some of the characters they're known for in parenthesis

Cam Clarke (Max Sterling in Robotech, Leonard in Ninja Turtles)
Ian James Corlett (Mega Man in Mega Man, Cheetor in Beast Wars/Beast Machines, Goku in DBZ (Ocean dub))
Scott McNeil (Protoman in Mega Man, Rattrap and Dinobot in Beast Wars, Duo Maxwell in Gundam Wing)
Peter Cullen (Optimus Prime in Transformers)
Frank Welker (Megatron in Transformers, Freddy in Scooby Doo, Abu)
Jim Cummings (Darkwing Duck in Darkwing Duck, Razoul, several other roles I cannot think of off the top of my head right now, because he's done so much)
Mike Judge (Beavis, Butt-head, Tom Anderson, Mr. Van Dreissen, Mr. Buzzcut and Principal McVicker in Beavis & Butt-head, Hank Hill and Boomhauer in King of the Hill)
Joe Alaskey (current voice of Bugs Bunny and Daffy Duck)
Luci Christian (Kaname Chidori in Full Metal Panic
Dan Woren (Roy Fokker in Robotech)
Richard Epcar (Ben Dixon in Robotech)
Wendee Lee (Vanessa in Robotech, Yuri in The Dirty Pair (Streamline dub), Angel in Big O)
Gary Chalk (Guts Man in Mega Man, Optimus Primal in Beast Wars/Beast Machines)
Peter Fernandez (Speed Racer)
Corinne Orr (Trixie and Spritle)
Eric Stuart (James in Pokemon, Seto Kaiba in YuGiOh)
Susan Roman (Sailor Jupiter in Sailor Moon)
Harvey Fierstein (Yao in Mulan)

There's more, this is just what I know off the top of my head.