I used something I think was called a Rackman at one point, which was a rack type holder for the Scholz Rockman. Next processor, like
@Akstrat and
@ScottyB was the ART SGX2000 with the X15 pedal (actually recorded with that one), tried the Roland GR33 with GK2 for a bit but never got very good with it. I was playing tube amps, mostly Mesa/Boogie, throughout that time. The FX units always put me back to just using the amp and a couple of stomp boxes... the sound wasn't there. You had to combine it with a good tube amp to get by. Next tried a Line6 POD, which was a fun practice tool, but that's it.
The first standalone to the PA solution I used (no amp involved) to actually play for pay was the Eleven Rack. I give credit to this unit for convincing me that digital could be good enough to use by itself, guitar to audience. Well conceived, well executed, and sounded good. Inspirational guitarists like Dann Huff were using it. Amazing. The Axe Fx was available by then, but I wouldn't have spent that kind of money for what I, at that moment, equated to a fancy rack POD. Boy, was I wrong! Having that success with the Eleven Rack inspired springing for my first Axe Fx, an Ultra, in 2011. Fast forward to now, and FAS is still the pinnacle of modeling, and I have since purchased three more units (progressively the II, XL+, AX8) and the last two are my main gigging units today.
All that said, I also just purchased a Mesa Road King II combo last week. Made a great deal with a nice guy, and I still love the sound of a good tube amp. I'd gig it tomorrow if the spirit moves me. You can bet, however, that even if I do there will be an Axe Fx in the line. Fractal Audio has forever changed the way I look at what you can get from an "FX box." I don't think of playing without thinking of shaping my tones with the Axe Fx. It's that superior.
Edit: I thought I should add, in light of some of the other posts, that I did have several rack preamps in between all that. A Pearce G1 that was pretty good for all solid state, a Mesa Studio, Mesa Quad Pre (this kicked ass with a Mesa 295 tube power amp into two thiele cabs), a Triaxis, a Soldano X88, and a Soldano X99. At one point I had the X99 and a huge purple Soldano stereo power amp that is probably worth a zillion dollars today. I have spent way too much money over the years.