It depends on the type of car; in a sedan I'll keep the auto transmission all the power features, especially the climate control (I have one of each and I hate having to screw around with the manual controls in the 240D). In a sports car, I'll take a manual transmission and no features at all.

The automatic stuff in my W123s is very simple to work on and very cheap to repair/replace, there is no reason to downgrade it.