I had a chance over christmas break to drive my uncle's '07 X S-package manual to and from our cabin in northern MN (the reason why I'm looking at purchasing a Jeep when I FINALLY graduate) and experienced the same thing. Got better mileage than most people here seem to be reporting.
It's funny...I joined this forum to get owner opinions of whether a Jeep was a good fit for me and the things I do, and meantime my uncle goes and gets exactly the vehicle I was eying, for the exact reasons I was eying it. Looks like Jeep is going to have another happy customer (ME!) in a year or so.
I was very happy with it, loved the simple interior and exterior (finally something that's not over-designed!), was impressed by how well the soft-top held heat in the sub-zero temperatures, and the freaking thing went right over the foot and a half of snow that covered the gravel driveway into our property, letting me get to our snowblower and clear a path for my dad. His 4x4 truck got hopelessly stuck and I had to pull him out.
The ride was exactly what I like. Stiff, let you know when you were getting past the grip-capabilities of the vehicle with a little bit of head-toss and shuttering, but not a drag on the 140 mile highway hike. Sound system was EXCELLENT and my iPod made the trip up and back a blast.
I averaged just over 19mpg, with most of it being highway, and the rest 35mph cruising over bumpy, poorly plowed gravel roads. I especially like how the engine let me use very low RPM's without lugging.