Tough choice as there really isn't anything out there that I like (including the 5thGen 4R)... I'd say the current Gen GC would be the one I would get if I couldn't have a 4thGen 4R.
I like the Tahoe (but a little larger than I want), LC (unreliable), Porsche (to expensive to fix), REALLY like the X5 (but it's a BMW, expensive to fix, reliability is questionable... I own a e90 M3, they build great performing vehicles)... I like the Merc AMG ML63, the G55 would be a player (but it's ugly)
In the grand scheme of things (comfort, build, price, repairs, towing) the 4thGen and the new GC are about the only two SUVs I'd consider owning.
If I tanked my '03 V8, I would probably buy a vvti V8 4thGen, a 5.7l Tundra, or a 2001/2002 Land Cruiser. I want a truck that will work all the time, be reliable, fixable...
Sidenote... I was coming home from a road trip and was tailing an ML63-AMG in my '11 M3, that Merc is fast, quick, and smooth for an SUV. Aside from the cost (and the fact it's a taxi in the rest of the world) it's a perfect light towing SUV. We were smoookin' and it was hanging on nicely.