Big fan of Entwhistle, Chris Squire, Flea, Les Claypool, Jaco, Stanley Jordan, Geddy Lee. Have to admit I'm surprised that no one has so far mentioned John Myung from Dream Theater! The man can flat out PLAY. Reportedly one of the few musicians to not only warm up before concerts, but also to religiously include a warm down after shows.
BTW: Colin Edwin of Porcupine Tree is a very capable player... not the fastest or most technical player around, but his grooves are just solid.... perfeclty mated to his partners in the band.