Number one has to be Chris Squire without whom I'd probably still be playing the clarinet.
Second is Dennis Dunaway - superbly melodic player and it's good to see he's been mentioned on several earlier posts.
Number three - John Entwistle. i spent many lonely nights in my room learning his lines.
Four - Jaco - I was blown away by his playing, especially his fretless work - inspired me to build my first fretless.
Fifth is Stanley clark. i absolutely love his playing .
A very subjective list and I've had to leave out a great many of my favourite bassists - 5 is not enough. I mean, how can I leave out the likes of Percy Jones, John Giblin, John paul Jones, Phil lynott, Roger Glover, Tom Hamilton, kasim Sultan and even Micheal Anthony. Seems like all my favourite bands of the 70's had superb bass players, alot of them concentrating on holding down the bottom end but an equal number pushing the boundaries.