Peter Sellers,Alan Arkin,Steve Martin,even a 007 (spoiler) all played the Gallic gumshoe.

I had no idea there were so many. No "Treachery and Greed of the Pink Panther"?

I also didn't know they had made so many of those! I think I saw the first one, and then the first Steve Martin one.

As a kid I loved the Peter Sellers Pink Panther movies, I watched and rewatched them whenever I could. My friends and I used quotes from them as inside jokes. During the DVD boom in the early 200s i bought a box set of all of them. I have yet to get through one. Every few years I put one on, but find them slow and unfunny. I still really like the animated title segments, but I have them collected in the animated series box set (the cartoons held up better for me!).
So my pick is "Dial "P" for Pink", one of the theatrical cartoons, from 1965.

The Return of the Pink Panther is my favourite. I also watched these over and over as a kid. I've never seen the Steve Martin ones, though.

The scenes with Clouseau and Kato were the best parts of the films.

^ This.