For me, its "clean as possible" and "flat as possible" -- EQ-wise, there are conservative dips and pushes from bass to bass with the exception of 8K, which I push +3db/+6db on all of them...I now do this from my pedalboard and leave the amp flat with only shelving on each end slightly bumped
For FX, I now use two Zooms and got to test-drive them in tandem at last night's gig : One Zoom, a B1on, is for the parametric shaping and I now have patches stored for each bass, and the other is for fx. On the B3 fx processor, I run compression on everything and use just that on most music (8:1 mostly as a "limiter") but I also use the "Jaco fretless" setting with bridge PU soloed and slight chorus for "faux fretless" on certain songs like "Smooth Operator" by Sade....a few songs, like "Boogie Oogie Oogie" by A Taste of Honey, I use Comp and Chorus.....I have a lot of processing power in the two Zooms available considering that I use them very very conservatively and sparingly as described above...The Zooms are quiet with cleaner settings
A parallel question to this would be: How many players utilize a horn/driver in their rig? For me, its a "must-have" but has to be dialed-in-to-taste