My top 10 in no particular order would be: Paul McCartney Noel Redding Jack Casady John Paul Jones Roger Waters Guy Pratt Les Claypool Cliff Burton Jason Newsted Steve Harris ...
haha I knew I forgot a couple .. like Entwistle and Geddy. I'm also a big fan of David Gilmour on fretless bass..
VICTOR WOOTEN!!! He is crazy good. He plays with bela fleck and the flecktones. If you don't know him check out this video and have a change of underwear handy - http://video.google.com/videoplay?docid=4118388908365727976&q=victor+wooten
i would have replied Mike Gordon and Phil Lesh last week at this time but after watching Les Claypool do his thing at the All Good festival last weekend I definitely have to add him to my list. he does some amazing shit with a bass guitar.
I'm shocked no one has listed Jaco Pastorius yet, I guess the title of the thread is subjective though My favourite would have to be Roger Waters, McCartney and then Geddy Lee.