Bought my 02 Yukon 6 months ago, and love it. Yes, she's a little thirsty (14/18), but it's like driving a Cadillac on a 4x4 frame (w/ a tighter turning radius!) Fun to drive, safe in a wreck, and the easiest interior configuration I've ever used. As a gig musician, I'm always loading/unloading varying amounts of gear. This rig is so easy to pull seats out, rearrange space, etc.
Bought the Yukon new in Dec. 2001. Drove it for business (mostly highway) to around 180,000 in 2008. Since then my sons have taken the truck to college with them. Now has approx. 215,000. I have always changed the oil between 3-5000 miles. We have only had to do routine maintenance (brakes, belts, tires etc.) The only irritating issue has been the drivers side window motor. Have had to replace this 3 times. Otherwise very, very solid truck. In fact, bought a 2009 Yukon and love it. The key to any car is to keep up with routine maintenance and don't beat it to death. Take care of your car.
Call me crazy but I bought a 2002 Denali with 120,000 miles on it. I have had it for two months (5000 miles) and am very pleased. I would have never thought to buy a vehicle with that many miles but the previous owner took exceptional care of this car. The ride is very nice although if the road is bumpy so is the ride. The performance is outstanding. It flat out moves when you give it the gas. My biggest complaint is that the front seat doesn't quite go back far enough. The mileage is at 16 mpg with about 50/50 driving. The car's transmission was rebuilt at 110,000 miles. My mechanic said it was one of the nicest cars he has seen with that high of mileage. Inside and out.