Aeriths death wasn't all too dramatic to me, but what DID make me cry, and is personally my saddest video game moment of all time, is this gem here.
Seeing that scene after playing the first game and seeing its bittersweet ending, is just soul crushingly sad.
EDIT: I honestly wonder if anyone can watch that and NOT cry, especially if you played the first game.
EDIT2: Edited the video, because seeing the scene in its entirety is WAY more sad than if you just saw the FMV. Get some tissues ready people. PS. Scene ends at about 4:29, then Manah just goes insane and the game gets crappy.