Whew, so many good ones. don't forget vaughn mason and cameo bit off of already done bass lines. james jamerson was sick with it. but only one so, I gotta go with the best R & B bassist of all time:
<iframe width="420" height="315" src="//www.youtube.com/embed/Hs-F9Pk4xH4" frameborder="0" allowfullscreen></iframe>