I've used a JC-120 for years, and I agree that it sounds awesome with pedals --- certainly the best of any amp I've tried. The JC-120 has a very flat clean tone, which makes it the perfect blank canvas for FX.
I've seen untold people on GuitarGeek defame the Boss DS-1, but I swear, it and the JC-120 sound like they were made for each other. This is the combo I've used practically since I started playing guitar, and I've had people rave about how awesome my tone is. Thank you, Roland Corporation.
And as mentioned, you can get JC-120s on Ebay for ridiculously cheap. There are always several on Ebay at any one time, and I've routinely seen minty examples go for under $400. Quite a steal.
When life hands me lemons, I have something to put in my vodka.