I have had my 2002 Z-71 since November. I LOVE this vehicle! I have been driving 20 years, and have had 15 cars (a bit of a car fan), but will definately keep this baby until she doesn't run anymore, and if they are still around will get another. My wife (who was dead set against this "Monster") even mentioned getting a Z-66 for herself. The AV is without a doubt the best vehicle I have EVER owned.
This site is a great resource as well, but don't let the "problem" areas of the site scare you. I didn't find the site until right after I bought mine, and in reading them I was terrified. I have had no problems with my AV, and even if I should in the future, I know there are 7,000 other owners here who will help in giving advice on what to do to fix the problem. This site is one of the best benefits of being an Avalanche owner.
Good luck