Geddy Lee (Rush)
Tim Commerford from Rage Against the Machine.
also Justin Chancellor from Tool.
Vic Wooten (check out his work with Bela Fleck and the Flecktones <Bela Fleck is an amazing banjo player>)
Bootsy Collins (trail blazer, Snoop Dogg and Dr. Dre sample him almost exclusively)
Phil Lesh
Les Claypool (though alot of his work uses effects)
John Paul Jones
I know its not all time great or upthere but I gotta love what this kid is doing
http://www.youtube.com/watch?v=JneG_DeHBfs
Also, Charles Mingus was amazing... check out Haitian Fight Song.
Ian Hill -Judas Priest
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I'm going to have to go with Sting. As talented as anyone, more than most.
Paul Gray is up there (partly because most of Slipknot's best stuff ws written by him).
Also Johnny Christ from A7X.
The flea is up there to IMO, but my bass player knowledge is fairly limited.
Les Claypool and Cliff Burton. Hands down.
I don't know if I could pick a "best" bassist. My favorite though would be Geddy Lee.
Your grasp of the obvious is inspiring.