SWR, Eden and other "california" voiced rigs = smooth Jazz and 80's/90's fusion. It takes a lot of tweaking to get a passable rock tone with these. Great for slap funk if you like that sort of thing. (I don't)
For Rock, the Ampeg tube SVT
or Ashdown ABM are the standards at the moment, both delivering "the" tone. (the SVT
is THE standard) Ashdown is really flexiable in that you can dial in a scooped "california" tone as well if you need to for some reason. (Ashdown used by U2, Radiohead, Paul McCartney, Roger Waters among many others...)
Another great rig is the Ampeg B-15 combo. great for rock and soul especially. great studio amp, not suited for loud rock shows. A vintage silver faced tube Fender Bassman 50 (or 100) head can also be really cool, but again is relegated to mostly studio work due to low wattage.
Bass Driver DI is great as well, both as a DI and an effect run in front of an inferior amp. In my experience, it can really deliver "tone" no matter what peice of crap you run it through or into.
As far as Basses go; a vintage or at least USA made passive Fender (P or J) would be the standard. Active, the Musicman stingray
really is the best (Tony Levin) although G&L makes some pretty flexiable designs, both passive, active, and switchable. Not surprisingly, all of these designs are those of Leo Fender who started, and designed the instruments for, each of these companies.
In boutique land Sadowsky, Lull and Lakland are the most well liked, however their designs are custom models based again on the vintage Fenders. Aguilar is a boutique amp company that makes some amazing tube bass amps, although they are more Hi-Fi than most vintage and vintage inspired amp designs. Orange is also making some great all tube bass amps.
For me (a bass player) it ends there. Sure there are lots of other options but these really are the "best of the best" and what you hear on most of the best loved records ever made. (ok so Paul played a Hofner through a vox...)