The answer is dependant on whether newness is important to you. Otherwise, I think the clear answer is one of the "time warper" W123 240Ds with manual transmission that occasionally appear, usually in Florida, that have been garaged their entire lives and look, drive and handle almost like new. For the W123 series, very little problems or significant maintenance (fluid changes and valve adjustments only) over extreme periods of time and mileage are the rule with very few exceptions that I know of (I personally know of none that didn't involve abuse). A little slow, maybe, but with a stick and learning how to drive them properly, most drivers have no problems on the interstate or in the city.

Just a biased owner's thoughts who feels that having electicity involved in only your lights, starter, glowplugs, radio and AC blower is a good thing for reliability and longevity of your car.

__________________
2008 GL320CDI 6K
1970 280SL 112K
1982 240D 210K (Sold)
1973 220D 220K (Sold)
1967 200D 160K (Sold)
1992 400E 139K (Sold)
1988 300E 148K (Sold)
1987 300D 257K (Sold)
1991 300E 108K (Sold)
1987 300E 131K (Sold)
1978 300D TMU (Sold)
1980 300D TMU (Sold)
MBCA Member