Billie Piper
Doctor Who: The Doctor and Donna Was Always The Right Endgame
In Doctor Who, Donna Noble was the most adult friendship The Doctor ever had, and his retirement with her and her family was his best ending.
Doctor Who: Christopher Eccleston Wants Folks Sacked Before Return
Christopher Eccleston wouldn't consider an on-screen return to Doctor Who as the Ninth Doctor unless Russell T. Davies & others were fired.