Your favorite Pink Panther movie?
For me, it'd have to be this one.
As much as I like the first two films (especially A SHOT IN THE DARK, one of the finest comedies ever produced), I think I prefer the three later ones with Sellers the most, because it allows him to focus on being as silly and bumbling as possible.
RETURN OF THE PINK PANTHER is my favorite of the bunch because it gives Sellers plenty of room to his brilliant slapstick bits (one of my favorites is when he disguises himself as the phone repairman).
...STRIKES AGAIN is generally regarded as the funniest of the series and I enjoy it just about as much as RETURN OF THE PINK PANTHER.
The only problem I have with REVENGE OF THE PINK PANTHER is that there are not as many memorable scenes as there are in the others that I mentioned. Not that there aren't some very funny scenes, but in general I don't find many of them quite as memorable (with the exception of the inflatable parrot). Still, a hilarious movie.
As for the last three movies (TRAIL OF..., CURSE OF..., and SON OF...), these have some funny moments but I think my opinion of them is rather low because of the fact that Sellers is not in them (unless you include the use of outtakes in TRAIL OF..., which I don't really count). As much fun as the series is, its rather sad that Sellers wasn't around to appear in the later films, and that those later films were made with other comics standing-in for the Sellers-type role.
However, being a fan of slapstick comedy, I'm ultimately glad to see the series had continued just because good physical comedy is becoming harder to see. I hope the new PINK PANTHER movie manages to contain some good slapstick and perhaps inspire some more films in the series, but only if they're done well.