Not that I am recommending them, but I am almost at 60k miles and still on the original Goodyear Wrangler AT's. They are almost at the point of needing to be replaced. I am running the factory 20's (275 65 R20).

After tire shopping recently, I sure wish I had the 18's! Better selections and a bunch cheaper.

I have seen good reviews on the Michelin LTX A/T 2 All-Terrain. I am considering going w/ them, but the tread does not look very aggressive for an All-Terrain.