(Is not actually God, of course. God is Morgan Freeman)
Living proof that sometimes, all you really need to be a Badass is the perfect voice. A noted actor of stage and screen, James Earl Jones is famous for his deep voice that can either be sinister (e.g. Darth Vader) or paternal (Mufasa) but is regardless authoritative and commanding — even more so when you consider he had to overcome a severe stutter in his youth. His voice is also remarkable for being naturally of bass register, which is indeed very rare. He gets a fair amount more respect on the stage, where he was a fixture on the African-American art-theater circuit (he was the lead at the opening performance in several of August Wilson's Pittsburgh Cycle, most famously Fences.)
Recently received the SAG lifetime achievement award. And he's scheduled to receive an honorary Academy Award in 2012.
Here is a clear demonstration of just how perfect his voice is for the role (or rather, a demonstration of how lame things would have been without him): A pre-voiceover clip showing Darth Vader voiced by his on-screen character's actor, David Prowse, who had the right stature for the character (as James himself was too short).