Doctor Who - Series 8

RDJ would be much better than most actors people want as the Doctor (too many people want Daniel Radcliffe or Rupert Grint...maybe in 20 years guys). He'd have to stick with his British accent from the Sherlock films though. Time Lords tend to speak with Received Pronunciation and, despite the Doctor having the occasional Scottish or cockney accent, it would be even more odd if his next incarnation had an American accent.

Nah, RDJ is a definite no-no. He's had iconic roles already, as both Iron Man and Sherlock Holmes. If they were going to hire an actor, they'd want people to see them as the Doctor. It kind of ruins the effect if the star is already iconic for other roles, because then The Doctor is just one of many, rather than being "the big role".

Like Matt Smith, he wasn't just The Doctor, he was also an ambassador for the show, he was simply known as "The Doctor", because it has become his defining role.

That's also why Daniel Radcliffe wouldn't work.