Just wanted to add that I never really got flats (despite having experimented with a few different sets) until I played a mates vintage P bass with some La Bellas on - Total game changer. I immediately got some 2nd hand 760M's from here and after a bit tweaking the setup of my bass they settled nicely and sound/feel great. They needed to 'break in' a bit though. I've just bought a set of 760FS for my Jazz bass and they are great straight put of the packet. Very even across the strings, not 'sticky' as flats sometimes feel and full of lovely thump tone.
So, my vote goes for La Bella's - 760M for a P and 760FS on a Jazz. Oh, and 760QM quarter rounds for my Tele Bass.