Megatenist said:
EDIT: *facepalm* at myself for not even thinking of David Hayter
And so you should facepalm for that voice is truly amazing. However despite his amazing gravelly Snake tones, I don't know about his versatility, which is the mark of a good voice actor. Phil La Marr is rather awesome, not only voicing vamp, but also voicing parts in Futurama, and a host of other games and cartoons that I can't recall right now. Also Mark Hamill, voice of the Joker for many years, and also Wolverine in the last game about him. He is rather good too.
As for worst, I don't know, that would mean me looking up bad voice actors on the internet and if they're bad, why would I want to know more about them?