Out of interest, the new BMW diesels are so good, many of us Brits now chose them in preference to petrol cars - not just for cost reasons but for driveability too.
My last E46 touring averaged 48mpg over 80,000 miles. I recently test drove an E90 saloon with the new 163hp 2 litre diesel (320d) and it is a match for a petrol 330i for acceleration between say 30-50 or 50-70 (the figures back this up).
OK you can tell it's a diesel from outside and at idle and up to 20mph from inside, but at cruising speed it's whisper quiet. Over 600 miles on a tank of fuel is easily achievable too.
I was 'forced' into diesel due to costs, but wouldn't go back to petrol now unless it was significantly cheaper to do so.