I averaged between 45 and 46 MPG over 50,000 miles with my 320d with the best ever being 650 miles between fill ups. With the last two 330d (autos) we've only got around 26 to 27 with lots of town driving, (better than the M3 mind you which was just about making 18). My wifes using the car for longer journeys now and it has crept up to over 30. Hopefully the 335d will be even better.
Previously: 2007 335D MSport E90 Le Mans Blue, 2004 330D A Sport Silver Grey, 2002 330D A Sport Saphire Black, 2001 320D SE Touring Titanium Silver, 1998 M3 Evo Techno Violet, 1996 328i Sport Montreal Blue, 1994 325i Coupe Red, 1989 325i Sport 2 door Dolphin Grey,1986 325i SE 4 door Lachs