For me it would be Roger Waters. Not the greatest bass player in the world, probably not even in the Floyd as well, but that tone is his 100%. And part of his great tone is due to the Rotos he's been using since the beginning.
I realised recently that every time I get or make a new bass, I'm trying to cope the RW tone and this always leads me, one way or another, to Rotos. These days I'm playing with roundwounds, switching between Nickels and Stainless Steels, to find out which I prefer more.