Got back from SC, drove one shot to SC but did an overnight stay in Virginia on the way back. I will break the trip down as follows

-Exit 17 to about exit 5 on the NJ turnpike, doing 65 mph, easily 26 mpg w/ auto cruise)
-From exit 5 to Virginia, 24.5 mpg, about 75 mph, on this section you are ascending all the way so the engine is working a little harder (w/ autocruise).
Virginia to SC, 22 mpg, here you are in the 70mph zone and I was doing about 80 and once in a while having a little fun. No auto cruise

On the way back, I was having a little fun, rarely used auto cruise, overall trip back I got around 23mpg, travelled during the day so there was more traffic than on the way to SC.

Things I enjoyed about the X5:
Very comfortable. I dont have the special seats though
Lots of room for luggage
The auto cruise gives a certain feedback, something you dont get with other cars, its hard to describe but its a pretty cool gimmick.
The lighting is amazing, used fogs when there was traffic and I could see at least 180 degrees around me. The Flash light made it seem like it was daylight.

Problems:
Well about 50 miles from SC, a warning sign went on, fortunately she just needed another quart of oil. Took it to Myrtle Beach BMW and funny enough they charged me $8 for it.
Auto Cruise is for Prius drivers:)

Are you talking computer MPG or actual MPG. My computer's a little generous in it's estimate. Actual MPG the best I've seen is 24.5. that was a trip from NH to NJ on cruise 72/73 Soon as you see traffic or city driving....it's a pipe dream. I don't however recommend doing more than 500 on a tank. I did that about 6 weeks into owning the car and was stunned by the 20.8 gallons of gas it took. That's a little close for comfort. That day I learned this was no Japanese car, when it say it needs gas, it's not screwing around. You've got 40-45 miles before you SOL on the side of the road!

This is using the OB computer. I was reading about how Hyundai Elantra owners are unhappy with the combined mid 20mpg they are getting, they should have bought an E70