Hm...well, as others have mentioned, Mufasa's death in
The Lion King really gets me, even though I've seen the movie a million times now. It was just so heart-breakingly sad...poor innocent Simba. ;_;
And in
One Piece, though there's plenty of heart-wrenching death scenes in this anime, one that really got to me was
Spoiler Below the Going Merry's death. Good God, that whole scene was played off so well, it had me bawling. Especially Luffy's "MEEEEEEEEEERRRRRRRRRYYYYYY!" at the end. ;~;