I did a test drive of a 2009 Cayenne S a month of so ago, when I was thinking of trading my 335xi. Caught a boatload of **** from some of the forum members here then.
Ended up keeping the BMW for now, but I came real close to getting that Cayenne S. Seriously fun to drive for an SUV. It was priced around $30k, with 60k miles, I think.
Since the Cayenne S was at a Mercedes dealership, I also test drove a couple of their used M-B SUVs. The GLK350 was very nice and the used one they had was a couple of thousand $ less than the Cayenne S. Not as much power and not as much fun to drive, though. The ML SUVs were a little out of my price range.
The Cayenne S made me really want another V8. Must resist the urge to buy a 928.