Jar Jar: Meessa give up. Meessa give up.
Anakin: Are you an angel? (Awww the PAIN!)
AOTC:
The whole sand speech.
The whole fireplace speech.
The whole "I killed sandpeople like aaaanimals" speech.
ROTS:
Palpatine: No... No, No!! You're gonna die!! (or something like that)
Palpatine: POWER! UNLIMITED POWER! (although Ian McDiarmid did what he could to improve that scene)
Vader: NOOOOOOOooOOOOooOOO!!!
Anakin: What have I dooone?
Palpatine: (a sentence that beings with...) Once more the... (... what was WRONG with his voice?!)
Yoda: Goodbye, Chewbacca. Miss you I will. (What?!)