Keith David is downright brilliant in almost anything he's in, whether it's voice acting or John Carpenter's The Thing and They Live.
Also I've got love for John DiMaggio (FFX, Adventure Time, Futurama), Mark Hamill (the Arkham games as well as tonnes of stuff for Adult Swim), John DeLancie (Assassin's Creed, Quantum Conundrum and MLP), Tom Kenny (almost every fucking thing, he's widely considered one of the hardest working VAs in the business), Tarah Strong (this girl's versatile as fuck), H Jon Benjamin (Archer, Bob's Burger's, Lucy Daughter Of The Devil), David Hayter (obvious), as well as a fair few names that escape from me at the moment.
Damn nigga, if you don't have love for these guys, you're ignorant towards good VAs.