I am a die-hard Columbo fan and I guess all of the episodes, excluding the most recent ones, are my favorites. But Dagger of the Mind is one of my favorite favorites. It has wonderful performances by Honor Blackman and Richard Basehart and a familiar Hitchcock actor, John Williams.
This movie has one of my favorite scenes of all time - Blackman sobbing hysterically over a coffin and babbling to Columbo (we find out later she thinks he's from the press). In the midst of her over-dramatic performance, Columbo, in his most innocent voice asks, "Is there any way for me to get tickets? I'd LOVE to see the show." Too funny. Columbo is a great character. It's a shame that the last few episodes were not up to the wonderful standards of the old episodes and his comeback episodes of the early '90s. I haven't given up hoping he'll be back in top form before Falk decides to retire.