I've got 3 kids and a mother-in-law that lives with us. A couple of years ago before the birth of our 3 child, we had a full size Montero. We loved it, but it didn't have enough room. We sold it and bought an '07 Yukon XL. Love it more. Only wish we had held out for a 4wd one. The problem with most full sized SUV's is storage space behind the 3rd row. You'll know what I mean after one trip to Sam's Club/Costco. With the Surburban/Yukon XL's you still have plenty of room with the 3rd row in use. We went up to Tahoe last year and had no problem packing. That's with 3 kids in car seats, the wife, mother-in-law, and father-in-law. Everyone was comfortable. We've got a DVD player with headrest monitors and headsets. It was a very quiet drive.
Last year I also bought a fairly well modified '97 LX450. The main reason was for off road excursions. Places that the Yukon wouldn't do well. It seats everyone, but storage is an issue. I'm adding a roof rack and looking into possibly getting a trailer. Next month will be the first camping trip with it. I'm trying to limit gear and pack well. Only 5 of us are going on the trip. But with 5 people you're going to need stuff. So we'll see how it goes.
If you don't plan on doing serious off road trails, a Suburban/Yukon XL is a great option.
Wade
1997 LX450, factory lockers, lift, ARB front, Kaymar rear, 315/75/16 Pro Comp MT's, etc...