So I am thinking of buying an Orange Micro Terror. Would I be able to run pedal distortion through it if I back the gain right off? I have a really nice distortion pedal and I can run it through the clean channel on my other amp but not through a clean sounding distortion channel :/ Just wondering if the same would happen with the Micro Terror? Any thoughts? 
I haven't played a micro terror so I'm not sure what they're like but I used to own the regular dark terror and in my opinion if you're going to get a high gain amp (which is almost exclusively good for metal) then I wouldn't bother getting it if you want to just run a distortion pedal in front of it. Seems pretty pointless and redundant but hey that's just my opinion.
The MT is not the amp to get if you want to use a distortion pedal. The MT is only a single channel amp and while you can get "clean" by reducing the gain you also limit the output of the amp, if you want to get some decent volume out of it you aren't going to get the clean platform you want to run your pedal.

There are a few options, you could get the Dark Terror and use that amps distortion instead of a pedal, or you could get an amp that will give you a clean channel at the volume you need and run your pedal through that.

Without any specifics I am shooting in the dark as to what you needs actually are, and also have no idea of budget plays into things.