That's a fun question, I may make a list later.
But what springs to my mind as infallibly tearing me up isn't from a movie. It's from a TV show, and not a likely one.
"Mom? What are you doing? (quieter) Mom? (even quieter) Mom? (very quietly) Mommy?"
(Buffy the Vampire Slayer, episode "The Body")
Yep, eyes stinging now just writing it.
Dan
Absolutely one of the finest, most riveting hours the small screen has ever produced. And yes, I tear up as well when I see it. Anybody who has lost a parent can relate to it.