Some very interesting points...

I think Bryce's original post was asking for the archetypal profession for a Columbo villain, rather than the one that would give the best chance of avoiding being caught. (For the latter, it seems that being a nondescript individual with a boring job and no particular career prospects, but working in an organisation with an extremely famous, well-paid and arrogant boss would be ideal!)

The 'psychologist'-type villain idea was perhaps overused, and I don't think all of these episodes are too strong. But it taps into the idea that many villains are meant to be unusually intelligent, which possibly culminates in 'Bye Bye Sky High...'. To this I'd add the ones that have an obsession with technology: 'Playback', 'Mind over Mayhem' and even 'Short Fuse'. These villains can perhaps all be seen as being cut from the same cloth.

On the other hand, there are the more 'artistic' villains: writers, actors and musicians. Writers are particularly well represented ('Murder by the Book', 'Try and Catch Me', 'Publish or Perish'). If I had to pick one, then I'd say that Abigail Mitchell has just about all the character traits of the typical 'Columbo' villain.

I think it would have been interesting for the murderer to have been a Priest,Would have loved to see Columbo in and around the Clergy.

I enjoyed your response very much, Wendy! (No harm broadening the topic a little ) Those are great examples of recurring ways the murderer is often undone; in fact, it seems as though that watch/time business is in almost as many episodes as Dog!

I agree, tffff, that the "psychologist" episodes vary in quality. For me the truly standout episodes in this category are probably "Double Exposure" and "How To Dial a Murder", though even these, to me, have slightly weak endings. And it's an interesting point about the "technology" and "artist" categories. I think "Playback" is the best of the "technology" episodes, while my favorite "artist" episode is "Etude in Black"- probably the least compelling "artist" murderers for me are the actors, though I think such an occupation for a Columbo murderer has great potential.

And, Bugs50, I agree it would have been interesting for the series to have had sort of a religious backdrop (tastefully, of course) in an episode.

I enjoyed watching Columbo interact with the affable senatorial candidate played by Jackie Cooper, and also the affable Congressman played by an excellent actor who is unknown to me, in "Agenda for Murder".

So my answer to your question is politician, and I wish they had done more of those. Every once in a while I see one of our fine representatives on TV and I think, I'd love to see the Lieutenant square off against that guy.

I love that Jackie Cooper episode, too! The Nelson Hayward character in that episode seems to supremely represent two of the more contemptible things that many real-life politicians have been guilty of- unfaithfulness in marriage and being a hypocrite (Nelson campaigning against crime, yet being directly involved in it). I also love how his campaign manager, the victim, is a completely unlikable and revolting character, too.
I've only briefly seen parts of "Agenda For Murder", but I think I know who you're referring to- the guy who Patrick McGoohan's character is sort of in cahoots with. I agree that politicians make great adversaries, especially since they have so much to lose when Columbo catches them, so are naturally very contentious and defensive (sometimes to hilarious effect).