Normally I like Jimmy Stewart, and normally I don't like Frank Sinatra at all, so I'm a little surprised at how much I preferred Sinatra in the role of Mike. Or perhaps it's more that I preferred the character of Mike in "High Society" - he's a little more raffish, less stuffy, less naive.
I agree that Celeste Holm did the wisecracking Liz perfectly - she looked the part so well, too.
Cary Grant was magnificent in his role - I've always thought so, but once I saw Bing Crosby, um, not as good, it really comes home how great he is.
It was wonderful watching the two leading ladies - Hepburn really is the better actress, but Grace Kelly sure does have the ice princess down pat. As I mentioned above, she has the better wardrobe, too - that thing Hepburn was wearing in the library has to be one of the worst outfits I've ever seen.
Must have been pretty easy writing the screenplays - so much of the dialogue is identical, and must be direct from the play.