My amplifier is always a fat, clean, solid state bass amp. You can point and laugh and call me a "lead guitarist" all you want, buy I can't seem to get the sounds I'm partial to with a guitar rig, or even a tube bass amp-- I need it clean, and Ashdown (who are the natural descendants of Trace Elliott) have met my needs beautifully-- the MAG-300 has thick full tone, plenty of output, a usable (but not too drastic) EQ, and it sounds fantastic. Though I'm not actually using it as a "bass amp" (I cut the lows a little and boost the top for my work with Ubik, staying out of Joel's low end), it is great for its intended purpose as a bass amp as well as my weird, effect driven noodlings.
Though I have enough power to fill a small club without a PA (as does Joel), the sacrifice I have to make with high watt bass amps is: most gear meant to be fed by a real guitar amp (for whom 100 watts is high-output), like talk boxes and rotating speaker cabinets, are completely out of the question for me-- my amp will blow them up.
Acoustic Control Systems TC-410B
My cabinet was a Craigslist find-- I needed a 4x10 cabinet (I always play 4x10s primarily... if I'm doing real bass work, I might couple that with a larger speaker, but I seldom need to), and came across a listing for an Acoustic cabinet. This harkens back to a time when bass players would seldom get mic'd and fed into the board, and so the Acoustic cabinet sealed each individual speaker cone in its own cylindrical port, and to punch the sound out into the audience (I guess some guy named Jaco used to use these. "Jaco who?" I said). Anyway, this cab is louder at relative amp settings than any other 4x10 I've heard, sort of allowing the sound to "bloom" and disseminate out in the crowd. Awesome piece of gear; I got lucky.