I have an 06 Avalanche, and I just love it. (mind you we love on an acerage, so having a truck is pretty handy too)
Its very roomy for the family with the 4 doors. We drove home from Calgary with 3 adults a 3 year old, a 4 year old, and a 6 month old with minimal complaining. (5.5 hours or so) Plus we fit everyones luggage in the box, and everyones shopping purchases. It also has a factory cover over the box so everything always stays dry.
Also with the saddle bags, I still had a full socket set, wrenches, booster cables, and other stuff I like to have just in case.
It pulls our camper with no problems, (and its no lightweight) This picture is coming home from the lake, 2 adults, 2 kids, and our Rotty X Husky dog. No problem
However it IS big. My wifes Yukon Denali is probally a good 3 feet shorter.
Its got a nice turning radius so it doesnt even seem that big when parking.
It also has the AWD drive option (as needed) but you can throw in in full time 4x4 or 4lo as well.