Wow. Can't say enough about this truck. Was considering the Tundra 4dr/4wd. But that would have cost about $5,000 more plus a cover. If you take my price and compare it to what I would have gotten if I'd gone Toyota, you'd be amazed. The Avalanche has a better interior and a better ride (not as stiff). The utility is also better as the seats can be folded or the cover stored. It may not be as fast as the Tundra, but if you are doing hwy miles, you should get this. I traded in a 1998 Toyota. I'm impressed. No problems yet. I also like the oil filter/drain set- up. Much better than the competitors if you do it yourself.
Heated seats turn on with autostart in cold weather. Air conditioning turns on in hot weather in autostart mode. You know the psi of each tire. You can adjust all the light timing and chimes.
I really can't think of anything other than cooled seats and better gas mileage. You can get the cooled seats for 2009. As for gas mileage, you're going to get about 12-18mgp with all makes of trucks. I get about 16.7 which isn't too bad.