It depends on the venue...

We play an large outdoor venue for up to 300+ twice or more every week, and use a rack with a Mackie mixer, x-over, eq's and two Crown amps. Probably a kilowatt+... two 18' subs and a pair of JBL SR series 12" and horn top cabs (unbelievable volume, quality and reliability in those SR series!). Two 12" Peavey cabs for monitors. It's a lot of gear, but a BIG outdoor venue that needs fairly high volume (and it was designed for a full four-piece with a drummer, etc.). It stays at the gig.

For smaller outdoors, and indoor gigs we use the JBLs again, but use a Mackie 15" powered sub and a Yamaha self powered mixer (EMX2000-12), no monitors.

And several smaller restaurant and piano-bar gigs have house systems...

It just varies... Remember, I don't solo too much. So humping the gear isn't quite the problem solos, and older players have. Quality, volume (when needed) and reliability are our focus. We've used the deck rig for 2000+ seater outdoor concerts at full volume. No problems.

I can't recommend those JBL SR (now SRX) series too highly. You get what you pay for. 10 years+ playing a full band through them at close to concert levels, ON A BEACHFRONT without a single driver problem...

OTOH, I have never played through a keyboard amp that didn't suck (Peaveys, Rolands, Barbettas Carvins, Motion-Sound etc.) compared to those JBLs...