Chris Squire, Geddy Lee are my top two choices. Chris, in particular, gets some amazing tones out of his ("Heart of the Sunrise", the entire Drama album).
Cliff Burton, indeed!
John Paul Jones -- saw him play with Lenny Kravitz, once, he's too cool. (Some awards show.) Also an extremely talented multi-instrumentalist.
John Entwistle -- "The Real Me" 'nuff said.
Peter Hook (Joy Division/New Order) -- plays a lot of that high-on-the-neck stuff.