Breakfast at Tiffanys - Holly Golightly is so spontaneous, so whimsical, and yet so sad...
Holiday (1938) - Katherine Hepburn & Cary Grant, need I say more?
Cool Hand Luke - Paul Newman was such a man's man but still so hot. Probably the newest on this list (1967) so probably the only one originally filmed in color.
His Girl Friday - Another great Cary Grant film, GREAT dialogue, and as you should know, I love stories about journalists
Topper Returns - yes it's a sequel, but you don't need to see the first one (though it's good too)
The Thin Man - Nick Charles, the detective, and his wife Nora, the wannabe detective, oh how I love them!
The Country Girl - An alcoholic Bing Crosby with wife Grace Kelly. I don't know how such a goofy-looking man could have snagged a woman who looked like that! Bing proves his metal as a dramatic actor. Also stars another of my favorites, William Holden.
Little Women (1949 & 1933 versions) - narrowly made the list over 1944's Jane Eyre. The story is a classic and perhaps I love it so much because I have four sisters.
Love in the Afternoon - Audrey Hepburn and Gary Cooper, another winning combination of two of my favorite actors. An incredibly frustrating movie about an innocent young woman and a caddy womanizer...
Alice Adams - Katherine Hepburn in an uncharacteristic role.
As an addendum to this list, I must add on my favorite Alfred Hitchcock films:
To Catch A Thief
Strangers on a Train
The Lady Vanishes (1938)
Dial M for Murder
(Critics may argue that Vertigo is his greatest movie, and although I see that it was an incredible piece of work, I did not enjoy it.)
I think I may finally be out of film-list ideas;)