Started out with the Michelin Cross Terrains - the OEM's lasted 85,000 miles and still had lots of tread. I replaced them b/c they were getting dry rot cracked.
Bought another set of Cross Terrains. No luck the 2nd time around. After about 30,000 miles, they were looking pretty bad.
I bought a set of Firestone Destination A/T's and love them. You will not find an A/T tire as quiet as the Firestones. They look good on the Envoy, and are awesome in the snow/ice. However, in the rain they suck - I find myself spinning the wheels inadvertently sometimes when the light turns green!