if you can find a decent one for sensible money, the Mercedes E300 turbodiesel is awesome - mercedes have the diesel engine pretty much sussed, as do VAG dont even consider a yank oil burner, they are nasty.
my brother has the 97 (round head light) estate, its done 180,000 miles, has cost £50 in 3 years in repairs, and runs and drives like a new car.