i'm guessing the special, assuming it has a master volume, if keeping the thing quiet (while still getting overdrive) is what you want.
Not too sure about the built-in fx, though...
peavey are releasing a valveking super 8 (something like that) in the spring, it's going to be £129, according to gak, and it has a master volume... that might be worth a look, it's a bit cheaper than the Valve special, which is closer to £200, far as I know.