I use the Cooper STTs in 35x12.5x15. Fantastic tire on the road and in snow. I don't do much mud, but they've never got me stuck in what i have done.
They're not too great on rocks though. Even aired down to 11psi, i've had all 4 slipping against a ledge/rock garden that people with open diffs and swampers or KM2's just walked up. The side lugs are also chunking more than i'd like. I go real easy on the skinny pedal, and just idle through most rock patches in 1st low (4:1 case), and there are still large flaps and chunks missing from the side lugs.
I'll probably give another company a try when i replace these.