I just got back from a 2400 mile trip myself.

I averaged about 17MPG, but mine was mostly highway driving and using cruise control. My main observations are:

1. The X5 is very comfortable to drive long distances, particularly with the comfort seats. Play around with the settings until you get it just the way you want it...it will make a BIG difference in your comfort.

2. I am reminded that I didn't buy this car for the gas mileage!

3. 3rd row seat is only comfortable for the under 8 year-old set. And then it really isolates them from the rest of the car since the 2nd row sits high and the 3rd row sits low. 3rd row is okay in a pinch, but not ideal for long distance travel, even for small children.

4. Passing power is unbelievable!! (I have the 4.8)

5. Cruise control works nice! Cool feature of being able to increment or decrement the speed by bumping the cruise control stalk.

6. I bought a Rola hitch-mounted cargo box and it worked great...much less drag than the roof-mounted boxes (and easier to access, too!)

7. Xdrive worked very well in the snow and in the ice. The X was very steady, even in the worst of conditions.

8. I really liked being able to separate the movie the kids were watching and listening to via headphones from the Satellite radio! My other cars couldn't do this! I also liked that I could listen to the sat radio for several hundred miles without changing stations like you would on a regular radio.

9. I now understand why there is a divider in the center console! When my wife fell asleep with her arm on the other half, I could still access the console without waking her up! Nice touch!

10. I liked how I could keep the front cabin clutter free, yet still have access to various items in the deep storage bins in the door.

11. Speaking of those storage bins, each travel day, I loaded 2 to 3 water bottles in each door's bin. Those were life savers when the kids got thirsty and we could just say "pull a bottle out of the door pocket".

12. The 2nd row window shades worked very well, keeping a lot of glare out of the car (and making it easier to view movies, etc.

13. I loaded up two video ipods worth of movies, TV shows, etc and connected them to the rear entertainment system. This way, the kids had instant access to all the videos they wanted and we didn't have the extra bulk of a bunch of DVD's to haul around. I plugged them into the AUX port via cables. worked great. I used the same cables to plug into relatives and hotel TV sets, too.