I've seen a few that have gotten me misty over the years. Two that I would like to add:

"Return to Me".... The scene where David Duchovny pulls his dog away from the door and tries to explain to the dog that his wife won't ever be coming home again (damn, I'm getting choked up stitting here typing it...)

"Pay it Forward" I can't say too much about this one as it will ruin the movie.