Not going to try to talk you out of a wagon...a Suburban is a TRUCK, but the plus is you can fill all three rows and still have room behind the 3rd row for a ton of stuff. Fill all three rows in a wagon and you will be using the roof-rack or will have stuff on your lap. Also if you live in a hot area, the rear a/c sure helps a LOT...anyone in the 3rd-row is going to sweat in the summer in a wagon. I've had three Suburbans and a Denali XL and have dealy loved them all.
Now that being said a wagon will drive and handle a LOT better, and if you get an LT1 wagon, especially with the tow-pack, they flat RUN. They also get a LOT of attention...you just don't see them much anymore. And a big plus, especially on trips, you can get high 20's for mileage on a wagon, where 16mpg is "winning" in a Burb.
So there you go. I would not talk you out of either. I've loved my wagons and my Burbs. Good luck on the hunt!