Lately, it's an older Mesa-Boogie Diesel 15 - a big 'ol heavy duty thing on casters, that can handle about anything I'll ever throw at it, sounds fantastic at any volume, and there's the added benefit of; I don't mind leaving it in the the Harwell-Grice Band's Truck/Urban Assault Vehicle, hence, I don't have to heft it around. So on gig-days, that gets me down to carrying a 3u Gator zipper rackbag with a Crown XLS 1000 and this fine old red knob Alembic F-1X. The Gator bag has a pouch for all my cabling, and extras, but I always bring a bag with a couple more... because... me. Then there's the agonizing choice of which Alembic. Hard to go wrong there.
There will come a day when I'll sell the Mesa D-800/Bag End S-15D stack... and it will be a sad one. That rig sounds pretty dad-gum mean too.