Who is my favorite companion? Two words. Donna. Noble. She was the best. Her story arch was fantastic and so tragic. I identified with her and connected with her character deeply. She was thrown in with the Doctor and ended up turning him down the first time he asked her to travel because she was scared. When she realized she had made a terrible mistake Donna seeked him out and found him, and she was able to travel with him over all of time and space. Donna was so smart and sassy, she was the Doctors best friend and the most important woman in the universe. But she never believed she was worth anything. Behind all the barbs and sarcasm was a very insecure woman who felt helpless and unworthy. And when she for one brief shining moment believed she was important and that she could do anything, it was all taken away from her. She was returned to being just a temp from Chiswick with no memory of all the wonderful things she had seen or the amazing things she had done. It broke my heart in so many ways. Mad props to Donna Noble.