4. Helena Bonham Carter
Helena Bonham Carter has been in over sixty films and won, a boatload of awards. Shes played Queens, maidens, villains, and an ape. The role of the Doctor would definitely be in safe hands with her. Also, Bonham Carter is no stranger to the macabre. Having her as the Doctor could certainly bring a dark edge to the series, which would make sense, given that the Doctors disposition has grown increasingly dark over the years. Just think about it. All those regenerations, all those memories, all that loss, all contained in one mind; its enough to make anyone, even a Time Lord, a little daft. As the Doctors said before, he is definitely a madman with a box. I think Bonham Carter would bring out some (or a lot) of that, with more emphasis on the mad and less on the man.