I loved them all, from the cowboy/cop movies of McCloud and the whimsical whodunits of McMillan and Wife to Hec Ramsey's old west forensics, McCoy's elaborate con games, Amy Prentiss' pre-Closer/pre-Prime Suspect police suspense, Lanigan's Rabbi's comedy, and early Quincy melodrama. Of the Wednesday/Tuesday Mystery series, Banacek was my runaway favorite (what great impossible crime plots!), though the middle-aged private eye Tenafly is a sentimental favorite since I've e-mailed with James McEachin a few times. Great TV, great times.
Here's a related question: Can you name the special, one-off episodes of the NBC Mystery Movie, both on the Sunday and Wednesday versions? There were several -- mostly failed pilots plus one successful one -- but only someone my age (55) or so could probably remember almost any of them.
With a few exceptions the writing was truly fantastic. Very seldom has two episodes of the same series been nominated in the same year for Emmies, as was the writing of the first year.
These writers took care to make Columbo totally believable. Small things too, eg, winning a raffle, bowling league, Columbo belonging to the Holy Name Society which was a very nice touch.
I didn't know Peter Falk was difficult but I am glad he was.