Dawn French? Perish the thought! Though wasn't June Brown mooted at one point? That I would like to see...

More folkish Who-lore: the great Geoffrey Bayldon is often referred to as the best Dr Who we never had having turned down the part to play that more bumbling of hapless time-travellers Catweazle. He'd go on to play the Crowman alongside ex-Dr Who Jon Pertwee in the title roll of (love it or hate it) Wozel Gummidge which has its folkier aspects as well.

Matt Smith is a lot of fun meanwhile:

Doctor Who Prom 2010 - Doctor Appears