So many it's impossible to pick one so I won't...
1. Lassie Come Home, 1943 - Roddy McDowell, Lassie
2. A Very Long Engagement, 2004 - Audrey Tautou
3. Leon: The Professional, 1996 - Jean Reno, Natalie Portman
4. Beaches, 1988 - Bette Midler, Barbara Hershey
5. P.S. I Love You, 2007 - Hilary Swank, Gerard Butler
6. Philadelphia, 1993 - Tom Hanks, Danzel Washington
7. Penny Serenade, 1941 - Cary Grant, Irene Dunne
8. How Green Was My Valley, 1941 - Roddy McDowell, Maureen O'Hara
9. Ghost, 1990 - Patrick Swayze, Demi Moore
10. E. T., 1982 - Henry Thomas, ET
One glaring omission is Old Yeller, the 1957 movie staring Tommy Kirk and Dorothy McGuire. I never watched this movie and never will. I read the book and cried so hard I could barely see the words. Sad, sad, sad...