Although I too am in FaithNoMan's camp and love my JohnK Centurion and Century pedals, for an off the shelf, easy to find OD I'd look into the Shift Line Buzz. I always come back to that one for my main OD sound since it has a very edgy sound, but doesn't mask your bass's essential tone. Really great pedal. V1 is better than V2. The V2 version, although more versatile (more knobs) doesn't sound quite as thick as the V1. I've never played an OD pedal that sounds like my bass more than the Shift Line. Almost every other pedal I've tried is just too overpowering.
I just checked out numerous videos of this thing and holy crap- it sounds amazing! I think this would be perfect for my 'mild' crunch/OD, something I may leave on all-song for some texture. I run a pretty clean, crisp sound (Dingwall+M6+pick) with good attack, so something more subtle I can layer over top would be awesome.
This plus another heavier OD are probably where I'm gonna end up- thanks for that link. At least over speakers, sounds like the best solution to my ears so far for getting started. I'll definitely look for the V.1 version.