The reality is that I could easily get by with a Deluxe Reverb and a dirt pedal or two and a $500 guitar. Might even end up sounding better because I'd have a limited number of things that I could screw up...not to mention the fact that I'd theoretically spend more time focusing on playing... or theoretically spending more time figuring out how to get a better mix for the small club gigs we do (theories aren't always right though...) But where is the fun in that?
If you do mostly covers, and if you cover a range of material, a single channel amp is sort of tough if you really enjoy getting that dynamic tone that comes from a tube amp. There is just too much volume change using the guitar to clean things up if you want to get some really clean tones but also need some real dirt. I know it would help if we mic the amps and let a sound guy do his magic, but for the typical place that we play, it's not practical to keep the stage volume so low that this would work (to open up amps at all would make it so that the majority of the sound is coming from the amps unless we cranked up our overall FOH volume.)
You could go with a multi-channel amp, but I haven't met one yet that makes me feel the way that my single channel amps do. There may be some psychology involved in that because objectively, it's hard to argue with the tone coming out of...say...a Mesa Lonestar or a Mesa Roadster (haven't tried the PRS 2-channel amps...) But they just don't "feel" the same.
So, I end up setting up one of the great single channel amps out there (like my latest love, the DG30) setting it up to go from clean to crunch with guitar volume and using an distortion pedal for the rest. Nothing wrong with that, and for much of the material we do, I'm not using the dirt pedal anyway, so life is pretty good.
The next step in the Elmer Fudd / Acme Pest Control process was to use a BadCat Unleash with it's two channels of programmable level attenuation set up so that when I really roll the guitar volume back to clean up an amp set for dirt, I kick in the Unleash channel that has less attenuation to get the right volume. Depending on the actual output volume, this works pretty well (and recently worked out perfect) but other times, the combination of attenuator and the tone change that comes from rolling back far on the guitar volume just doesn't work well. Not to mention the fact that if I get confused and roll the guitar up before kicking in the channel switch on the attenuator I've got some unhappy band-mates (who have a decent sense of humor when it comes to my futzing, but they have their limits...)
So the culmination of all of this? I absolutely love the high gain tone coming out of the MDT, at pretty much any master volume setting that I'd use at club gigs. I absolutely love the DG30 for everything else. So, combine the two together into a "2-channel amp". I use a Radial head switcher that lets you dynamically switch between 2 heads into a single cabinet. It's got some fancy circuitry in it that takes the guitar input and routes it to the head in use, and loads the output of the head that isn't in use. Works like a champ. I've used this thing before, mainly to be able to dynamically A/B different heads I have. But using it live has been a real treat. Any cheap footswitch can be used to control the device, so my "dirt pedal" is the MDT.