-Saruman: You did not seriously think that a hobbit could contend with the will of Sauron? There are none who can. Against the power of Mordor there can be no victory. We must join with him, Gandalf. We must join with Sauron. It would be wise, my friend.
-Saruman: I gave you the chance of aiding me willingly. But you...have elected...the way of pain!
-Saruman: One ill turn deserves another. It is over! Embrace the power of the Ring... or embrace your own destruction!
-Saruman: So you have chosen - death.
-Saruman: Do you know how the Orcs first came into being? They were elves once, taken by the dark powers. Tortured and mutilated: a ruined and terrible form of life. Now...perfected: my fighting Uruk-Hai. Whom do you serve?
-Saruman: Hunt them down. Do not stop until they are found. You do not know pain. You do not know fear. You will taste man flesh!
-Saruman (v.o.): The old world will burn in the fires of industry. The forests will fall. A new order will rise. We will drive the machine of war with the sword and the spear and the iron fist of the Orc.
-Saruman (v.o.): We have only to remove those who oppose us.
-Saruman: Save your pity and your mercy. I have no use for it!
For Grievous related dialogue I would suggest: "Mutilated. A ruined and terrible form of life now...perfected."/"You do not know pain. You do not know fear."/"We will drive the machine of war"/"A new order will rise." Too bad we don't have Ian saying those lines, as they would make much more sense for Sidious to say.
Other Dooku lines to be on the lookout for:
-"The Jedi are using our army just as you said, my Lord."
-"Wait! You don't understand! He's---"