Hummers are extremely over-rated. Depending on where you live, you may not even be able to run a Hummer on your trails (Read: getting stuck between two trees that are 20 feet apart). Also, to whomever suggested to just "slapping on big ol' tires," a successful lift is much more complicated than that. The Hummers have an IFS, therefore you can only lift it so much before your CV's will be hurting, and occasionally breaking.
If you want to wheel cheaply, get yourself a foreign make. Isuzus, Toyotas, Suzukis, Nissans, and Mistubishis can all be into very substantial off-road rigs without spending a very substantial amount of money.
If you swapped in a 455 Buick, TH400, to an Atlas II Xfer case, Rockwells front and rear, triangulated four links, plus 44" Iroks all-around, you would have an off-road vehicle that could run with the best of them. Hell, just build your own vehicle from the ground up. (I can dream, can't I?)
All bullshit aside, what would you do with your Jeep? Would you ever take it off the pavement? Lift it for function, or lift it just for yuppie looks? Would you just keep it a mall cruiser?
Also, I must ask, why Jeep? Any old person can own a Jeep. Besides, Jeeps are for cheerleaders.