Every time a new Dr Who is about to be cast, the media start banging on about how "this time it might be a female". Even within the fantastical premise of Dr Who, Time Lords and regeneration, having him change sex is a stupid idea. The other daft thing that's often suggested is bringing back a previous Doctor or companion for the role. Luckily, they never go with any of these silly ideas. I have a creeping feeling they'll go for Andrew Scott (Moriarty in the recent Sherlock), or at least approach him, but I don't think he'd be right for the part.
I think Damian Lewis would be good but I doubt they'd ask, or that he'd accept.