I've had my 2008 e92 320d just over a week now. So far the car is saying 50.4MPG. Live and work in Lincolnshire so there's no motorway driving and plenty of tractors etc.
I'm impressed so far as this is my first BMW and the fuel economy was one of the deciding factors. Compared to my old car (2008 Mondeo 2.0 titanium x) this is a massive improvement as that averaged around 40 mpg!
I guess im being very sensible at the moment as im still getting used to the car. The MPG gauge is making me drive differently however, not so heavy footed when plodding along makes a big difference. And the gear change prompt uses 6th gear allot more than my old mondeo which never liked 6th until well into the 70 MPH range