Cool thread.
The best rig I ever heard in person on a larger scale was at a Gov't. Mule show. Warren Haynes was playing a Gibson Custom Shop Firebird non-reverse with Burstbucker pickups through his Soldano SLO100 head and ENGL 4x12 cabinet. And it was L O U D . The tone was nothing short of a revelation.
I'm convinced that, in these bigger environments, the power and depth that the P.A. puts out is at least as important as whatever the guitarist is using.
As for the best rig I've ever heard in a small to mid-sized club? My own.
(No kidding.)
That, or my best buddy's rig, which is a Collings City Limits Deluxe guitar, a Matchless DC-30 head and matching 1x12 cabinet, and some pedals including a BJF CAF, a D*A*M MkII, a ProAnalog Dual Drive, a Menatone Blue Collar, and an Area 51 wah. Freakin' amazing.
This same friend and I were actually just talking the the other day about how far we've both come in the tone / rig department. Gone are the days when I lust over other people's gear and tone. Same for him. It is indeed most comforting to have the knowledge that every time I plug in, at the very minimum, I will have a damn good sound. So every time I gig, my tone basically ranges from being damn good (at the very worst) ... all the way up through inspiring, earth-moving, mind-blowing, i.e.,
I am now that guy whose sound I used to lust over. (Still no kidding ... and I'm pretty proud of it, as it has taken me a very long time to get here.)
This is especially important because now there are no excuses. The proper guitar rig has been built, and the sounds I want are there. Now all I need to do is play good music and put on a good show. No more tweaking and knob twiddling. No more worrying about whether or not the tone is right, because it's always there. Now ... I get to focus all of my energy on just one thing: PLAYING my guitar. I have long maintained for myself that this is the purpose of gear in its essence: to provide the least amount of limitation to the user's self-expression. When you have the right rig and the right sounds, there are no excuses left. If you play a good show, you get all the credit ... same goes for a bad night.
Doc