Honorary Mention: Rowan Atkinson
In 1999 for a Comic Relief telethon on the BBC, Mr. Bean played the Doctor, as did many, many others. And Hugh Grant. By the by, any time you see a Comic Relief bit from the BBC, watch it, especially if it has to do with Doctor Who, they are always a hoot/
I put this here because it was cool, and not because I needed a way to make 11 Doctors stretch into 6 even posts...
#3 Matt Smith
The current Doctor, Matt Smith, came into the role with crosshairs painted on his back in giant, day-glo paint on day one. As the youngest Doctor in the series history, he also had to take the reigns from the most popular Doctor in recent memory, David Tennent. So, what made Smith work so well versus all the other Doctors that followed more popular actors? He made the role his own. He didn't try to out do anyone, or differentiate himself, he simply played the part as he saw it. There are moments where Smith looks his age, and moments where he looks all of the Doctor's 900 years, and those scenes often flow one into another.
This scene honestly gives me goosebumps.
Smith's run to date has not been without flaw, however. As much as I love it, and love Amy and Rory, the seasons have been a little too fairy tale-y for my tastes, but I do recognize that Doctor Who needs to be changed up often, lest it decends into 80's Who, and NO ONE wants that. Also the shows have been very focused on the Ponds, but seeing that as of mid season 7, they have been written off of the show, that has been rectified.
Wait....god dammit. What in the hell was I thinking?!
Long story short, the 11th Doctor's tenure thus far has been fantastic, managing to exceed the expectations of even the most stalwart nay-sayer. He has brought a silliness back into the roll that had been missing since the 4th Doctor, but still manages to keep a high level of drama in the mix.