Day 06: Favorite Special Episode
The End of Time, Part 2 (if you want to get technical!)
With almost everyone on Earth now recast in his image, The Master controls the world. He's shocked however when he realizes that one person hasn't changed. The Doctor soon realizes that the Time Lords are trying to return and re-establish Gallifrey. If they succeed, it is the end of time and the Doctor as we currently know him. Realizing that the Ood's prophecy will come true, he visits friends from the recent past.
The Doctor: I'd be proud.
Wilfred Mott: Of what?
The Doctor: If you were my dad.
Plus this moment with Rose makes it for me.
"I think you're going to have a very good year."
I love how it ended the way it started: not only for Ten but for David. He started filming with Billie then after a season she had to leave and here she is again, helping him end what they started together.