The mistake was not watching all sixty-nine episodes of Columbo, because that provided many hours of great TV watching. And also Peter Falk saying the word "panties" seven times in a row, but you can't have it all.
The mistake was mentioning this to friends who asked how I would rank those episodes.
Never ask an obsessive to produce a list based on quality. Case in point, I was asked about this in February!
Since then, I did what a responsible research addicted non-writer would do. I rewatched all sixty-nine episodes. I marvelled over Jack Cassidy. I sobbed with Janet Leigh. I tried desperately to derive greatness from that bloody Commodore. And, as I watched each episode, I wrote some quick fresh notes on each story.
From those notes, I gave you this list. Succinct being my enemy, I've had to cut this into a few parts. Also, much like Doctor Who, the biggest crime for me in TV is being dull. This might explain in advance why some stories from the seventies which are worthy but snooze worthy rank lower than some of the flawed but entertaining car crashes.
So without further preamble, here we go!