In "Friend In Deed" he asks the sales assistant (Arlene Martell) at the jewellery shop whether it is OK to smoke inside the premises.

I'd forgotten that one.

Nearly my favorite is his second scene with Milo Janus. The idea of Milo giving a health and fitness lecture to the detective investigating his murder is pretty entertaining. Obviously he just couldn't help it, but either way it's entertaining.

One of the best subtle scenes involving his cigar for me was in Forgotten Lady. The impatient butler has his flip-top silver dish, holding it out under Columbo's hand thinking that ashes are going to drop on the carpet. When Columbo notices this overt behavior, he just slowly looks down at his ciger in his hand, turns the ash-end toward him, just to verify that in fact there's NO ashes to flick in the tray, but nevertheless gratuitously gives the cigar a slight tap into the dish where absolutely NOTHING comes off the cigar. LOL