Some very interesting (mainly negative!) comments here. But, as the saying goes, for every bad experience you have you will tell 10 people, for every good experience you have you will tell 1 person.
I have a '07 220D SE but for only two months. I absolutely love the car. I have rattles and the infamous "crack" when the dash heats up. I also have the scratches on the boot lid where it meets the rear bumper. No major issues for me.
I had a bad start with the fuel economy getting only 31mpg on a full tank! But since then I have taken it back a notch and I'm getting about 43mpg (530 miles to a tank). I tend to drive on 50mph roads quite a bit so the car is being run at its most efficient speed a lot.
I think the comfort of the car is top of its class. I have driven executive A6s, BM5s and Merc Es and I prefer the interior of the Lexus by a mile. I also love the look of the car. That's primarily what drew me to the car originally.
Having said all of this, I haven't had any major problems so maybe I should come back in 12 months! I would encourage other readers to post if they have had positive experiences with their 220Ds. It would give a more accurate look to the statistics above.