1. Can't really choose just one, so I'll go with Three, Ten and Eleven.
2. Going with NewWho only: Donna
3. Again, NewWho only: Mickey. Unless Lady Christina counts as a companion, in which case there's no contest.
4. The Master
5. Probably the Catkind
6. Either Runaway Bride or End of Time - I enjoy Runaway Bride more, but End of Time is by far my most-watched episode. X3
7. Hard to say since I like the majority of the seasons
8. Probably Season 6
9. John Simm's Blond!Master would be my favourite, though I do also love Roger Delgado's Master
10. Father's Day. Gets me every. Single. Time. Possibly Vincent and the Doctor as well
11. Really can't choose just one, or even a top five - New Earth, Runaway Bride, Empty Child/Doctor Dances, Lodger, Closing Time, etc.
12. Empty Child, Silence in the Library, Waters of Mars and Midnight. Hmm, I'm seeing a pattern there.
13. I am the Doctor
14. I suppose that would be Martha, since I really like her character but a lot of people don't seem to.
15. Rose and Mickey can battle it out for this one. Again, unless Lady Christina counts.
16. John Simm and David Tennant
17. I don't know - there's no one who stands out in that regard
except Lady Christina Whatserface I must stop harping on about her but I really loathed that character and how she was played18. Catherine Tate
19. *cough* See #17, 'least favourite actor'
20. Steven Moffatt. Despite his issues with overly complex jumbled storylines, when he gets it right he's amazing.
21. Amy and Rory
22. Donna and Ten, unless the Doctor and the Master count.
23. Torchwood
24. Depends on the day, but a few are: "Oh, baby, I'm beating out a samba!", "[in answer to 'what are you armed with?'] This, overconfidence and a small screwdriver; I'm absolutely sorted!", "You're Mister Thick Thickety from Thicktown, Thickania! And so's your dad.", "Don't drop the banana! ... It's loaded with potassium.", "We definitely added to his pile of good things." Also, from Classic Who, the Doctor and the Master discussing why the Doctor is late.
Doctor: "Had troubles with Bessie."
Master: "Bessie?"
Doctor: "You know, my -" *mimes driving a car*
Master: "Ah. Well, it may interest you to know that
my -" *mimes driving a car* "- is aimed and ready to fire."
Plus, the Master watching Clangers and imitating their whistling is adorable, though not very quotable. And "You could rule your half benevolently," when the Master tells the Doctor he wants to rule the universe and is willing to share.
25. "Allons-y!"
26. Sonic screwdriver
27. Probably that one with John Barrowman. You know. "'Have you read it yet? Have you read it?'" *later* "'YOU READ IT!' 'YES, AND IT'S BRILLIANT!'" Though the interviews with John Simm are adorable, too - "I'm not very dainty about the tights situation." and "[about the crew scaring him with Master masks] Peeping around corners and jumping out at me with that... grin."
28. I'm not really familiar with all the gifs floating around. I do like this one though:
29. Derek Jacobi
30. Probably around six years ago or so? I can't recall exactly.