Re: Guys with big pedal boards.
Before the amp: preamp, compressor, tuner, distortion, wah, chorus, phasor.
In the loop: Boss Pitch Shifter/Harmonizer, delay one, delay two. (Will possibly add a tremolo pedal and a vibe pedal to loop.)
The Mesa amps have really good loops; the Mark IV and the Mark V are switchable.
Bill