A few favourites (11th is my favourite, can you tell).
"One more, just one. Is this world protected? Because you're not the first lot to have come here. Oh, there have been so many! And what you've got ask is ... what happened to them? I'm the Doctor. Basically ... run."
"Now, the question of the hour is, who's got the Pandorica? Answer: I do. Next question, who's coming to take it from me? Come on, look at me! No plan, no backup, no weapons worth a damn! Oh, and something else I don't have: ANYTHING. TO. LOSE. So, if you're sitting up there in your silly little spaceship with all your silly little guns, and you've got any plans on taking the Pandorica tonight ... just remember who's standing in your way. Remember every black day I ever stopped you! And then, AND THEN! Do the smart thing ... let somebody else try first."
"Imagine you were dying. Imagine you were afraid, and a long way from home and in terrible pain. Just when you thought it couldn't get worse, you looked up, and saw the face of the devil himself ... hello, Dalek".