I wish they'd go with a slightly older Doctor; I don't like that the character has to be seen as "sexy." I want the mad scientist, Gandolf-like, alien professor sort. I think I'd like to see someone less "young, pretty and hyper" and more of a ''weary,wise and strange." Although I think Matt Smith has the mad scientist down very well.
eta: I LOVE Alan Davies, but I think he's too well know as Jonathan Creek to be considered for Doctor Who.