i have a few favorites, though the dramatic often beat the comedic ones for me
the crazed Anakin on mustafar, i think i actually love this entire dialogue, but i'll shorten it
Padme- Obi-Wan was right! you've changed!
Anakin- I don't wanna here anything about Obi-Wan, the Jedi turned against me, don't you turn against me!
Padme- I don't know you anymore!
-when Anakin sees Obi-Wan at the top of the stairs-
Padme- -Looks around, and sees Obi-Wan- No!
Anakin- You're with him, you brought him here to kill me! -starts to strangle Padme-
Obi-Wan- Let her go Anakin!
-Anakin continues the strangling-
Obi-Wan- Let her go!
Anakin- You turned her against me!
Obi-Wan- You have done that yourself!
-when Obi-Wan has cut off Anakin's legs-
Obi-Wan- You were the Chosen One!
You were send to destroy the Sith not join them!
Bring balance to the Force, not leave it in darkness!
Anakin- I hate you!
Obi-Wan- You were my brother Anakin, I loved you!
Anakin- -Screaming of pain-
And there are some small ones
Mace Windu against the 'dying' Palpatine:
"I'm going to end this once, and for all!"
Han Solo on the Desert Skiff
"My sight's getting better, instead of one big black spot, i now see one big white spot."
don't you just love patriotism...