SimpleMind - Rick has a 2006, it's a 3.0 (the 2.5 was discontinued in the US for 2006).
It definitely has a lot to do with where you live. In the X3, I was getting 11.8-12.2 mpg city; highway I could squeeze 23-25mpg, but that's only on long trips. There aren't too many places I need to go that I have to get on the freeway. There are a lot of hills in San Francisco and they take a toll on your mileage. Also, pretty much everywhere you need to go in the city is stop-&-go traffic. Although stop-&-go is bad for gas, it would be better if it weren't on hills. Sure you get good gas mileage going down the hill, but you don't save as much as you used getting up the hill. I'm sure living out in the flat country, anyone would get good gas mileage. But places you need to go might be farther away.