Most not realistic
Apart from the fun aspect not really sure of the point of this poll.
No film actor is going to be chosen simply because the BBC wont be able to afford them.
Chris Eccleston was arguably the most famous pre-Who actor in the rebooted series - the trend has always been for existing BBC drama actors but with the trend being for them to become less and less well known.
I'd like to see a non-flirtatious woman in the role - if only to eliminate the obvious romantic angles that keep recurring in the reboot. Has there been one companion in the reboot that hasnt harboured strong feelings for the Doctor? Even Donna's spark waned towards the end of her run.