A few I follow here:
Lee Sklar - nuff said
Cici bass - also seen on Anderton's All About The Bass
AMP - Reviews n that
Dr Funk - good if you like slap. I've seen him busking in Falmouth and he is really good
Gev Delano - very talented kid
Jermaine Morgan - lessons, demos, etc.
Rumblin Man - demos of bass and guitar stuff
Some non-bass stuff:
Alison Eales - friend of mine just released her first album, go check it out because it's awesome (and I'm not just saying that because I'm biased)
Dominic Noble - book reviews
exurb1a - philosophy and stuff
J Draper - History
Nicole Coenen - lumberjacking lesbian and, er, something Canadian starting with L...
The Charismatic Voice - music reactions and vocal analysis from an opera singer, teacher, producer, etc.