I have to punt Boss man, those pedals all rock...I like the Mt2, but, it is over rated...The Ds1 is killer, but the od-20 twin pedal kills them all as it has both of them and many more distortion souds on it.
It does cost slightly more than a single boss pedal ( I saw them for about 170usd on zzounds.com) but it rocks.
Also look at Line 6 Dm 4 pedals, but they cost lots.
Tech 21 did summin called a comptortion a few years back and that rocked.
also try visual sounds Jeckyl and Hyde pedals...also cool

Good Luck finding that perfect tone, if you do, let me know what you used