I've heard mostly negative things about using a distortion pedal for your tone. The times I've tried using them certainly didn't go well for me, and I got better results using the Amp's natural tone. Still, there's good pedals out there from what I've heard, so whatever. Also, the ENGL Powerball mentioned down there is supposed to be fantastic, based off what I've been told.
Anyway, awesome thread. I had considered making one of these.