Someone mentioned tranny & window regulator problems in the 1997 E320 (W210).
This is actually the reason why I've stayed away from the 5-speed electronic tranny and any MB newer than 1995.
I really think that aside from head-gasket problems (MB has fixed the head-gasket, with a 3rd for 4th revision) and potential evaporator problems, the 1986-1995 W124's and the W126 S-Class are one of the most reliable and well-built MB's PERIOD.
Moreover, parts are plentiful and inexpensive compared to BMW, Audi, Lexus, Infinity, and the like marques. And you can actually work on them and their little switches (I've rebuilt two seat switches, and I window regulator (new grease & brushes)).
I've been lucky (knock on wood), no evaporator or head-gasket problems.
I do have intermittant ASR problems on the 500E, but I have good plan of attack. So it will be under $500 in parts.
1988 360TE AMG (158K)
1993 500E (75K)