I play a little bit of everything... I'm in a hard rock/funk hybrid band, also in a 25-piece jazz band, and I've been known to record some progressive instrumental stuff when the time permits... I need versatile amps!
That said, Mesa has never me down. My main rig is a Triaxis and a 2:90. I honestly believe that it is the best mix of tone and flexibility available anywhere. Loud, heavy, expensive to retube, but worth it in every way!
I also have a Mark IV (was my main amp for a while, now my backup). For a combo, it's got a good tone/flexibility thing going. Took me forever to find my tone using it... I think it took me 3 months to find it. Then I wrote my settings down everywhere, so I wouldn't lose them. To me, it's not a good amp for beginners, because it's got so many controls and they all interact with each other in strange ways. But, it is a great combo--I like it because it always sounds great with a guitar plugged straight into it (no FX).
I've also used a Nomad 45 for a while... another killer amp. Not quite as flexible as the Mk IV, but a lot simpler to use. I always thought the Nomad was voiced a little darker, maybe a little dryer (less liquidy gain) than the Mk IV. It had a little more of a vintage tone to it. Coolest feature: the built-in solo boost!
I'm looking for a new amp now...a Mesa Subway Rocket to use for impromptu jamming--I played one at GC the other day, and aside from the fact that it was beat to hell and completely microphonic, still managed to kick ass.
Well, what can I say... I'm a Mesa fan!