User blog comment:Uknownada/Top 10 Emotional Moments/@comment-3125914-20120630052015

Aside from those already mentioned, I'd like to add:

Sanji's goodbye to Zeff: it can't be compared to Straw Hats' ferwell to Vivi, but I still found it very emotional since it's Sanji showing his gratitude to the one who saved and raised him.

Otohime's death scene: Despite the chaos and confusion around, Otohime still told her sons not to be angry for her, not to mention that she was facing her own death.

Luffy's and Vivi's exchange of fists: It's the moment Luffy pointed out that Vivi was fooling herself for wishing nobody's death. After she explained her point of view, Luffy asked her why was she risking her life. Vivi's answer was quite moving: "I don't have anything else to risk!". And what made this moment so emotional was Luffy's reply: "Try risking our lives along with yours! We are your nakama!".