HAL 9000 is currently in a villain deathmatch against Agent Smith from The Matrix, and he's winning (click here to vote). Why? Dat voice. HAL was voiced by Canadian actor Douglas Rains (still alive, by the way) in a cool, conversational manner that ends up being absolutely chilling.
Who has a cooler, more conversational manner than H Jon Benjamin, comedy star of Archer and Bob's Burgers (among other things, but that's where you know his voice best)? Nobody. Which is why having J Jon do HAL's lines in this clip from 2001: A Space Odyssey was such a great idea.