I definitely agree with "It's a Wonderful Life." The part that gets me is Harry's toast to George - "To my brother, the richest man in town." My eyes are welling up just thinking about it.
Others, scenes included (spoilers):
Field of Dreams: "Dad, wanna have a catch?"
Sling Blade: Karl says goodbye to the boy
The Hours: Ed Harris' character's suicide; Virgina Woolf lays down by the dead bird
Saving Private Ryan: Yes, I know Speilberg is manipulating us, but the death of Giovanni Ribisi's character gets me. "I want my mother."
Dead Man Walking - end
American Beauty - end sequence with Lester's narration
Many, many more...