This is really hard. It's difficult to choose between all my favorite characters and say "that one's my favorite actor." But if I had to do it, I'd say David Tennant. He really brought a lot of personality and character to the Doctor that his predecessor didn't. He made the Doctor less military and distant, and more friendly and accessible. He brought himself into the role, and really convinced me that he actually could be the real Doctor.
Plus, that hair and boyish face just can't be overlooked.
Least favorite actor:
The guy who played Mickey. Mostly because I didn't like his character. At all.
Karen Gillan, for many of the same reasons as Tennant.
Least favorite actress:
The chick who played Martha. For the same reason as Mickey.
Favorite Writer: No idea.
Either the Doctor and River or the Doctor and Amy.
Favorite Spin-off: Don't have one.