I don't think anybody really expects a proper, full-on, bye-bye-David Tennant, regeneration next Saturday, do they? But the fact that there's a little element of doubt sneaking into your mind tells us that ol' RTD has played a blinder, this time.
Discussing this elsewhere with the usual suspects, I made the point that casting a new lead for DOCTOR WHO now requires the actor to come from a rather select group: British actors who are borderline movie stars (like Eccleston and Tennant), who still seem comfortable taking jobs in TV. So, in no particular order, we've got:
Bill Nighy (nearly got the job over Eccleston, apparently); Robert Carlyle (has been asked about it in the press before, and refused to rule himself out); Idris Elba (recently did that Alexander McCall Smith thingy with the BBC); Chiwetel Ejiofor (hasn't done much TV for a few years, though, but does seem to do a lot of SF); James Nesbitt (ruled himself out after rabid reaction from fans when his name came up after JECKYLL, around the time Steven Moffat was first rumoured to be taking over as show runner); Jack Davenport (again, an actor with lots of previous with Moffat, looked great swashbucking through rainforest at the climax of the otherwise-atrocious PIRATES OF THE CARRIBEAN 2, and was in one of the last great UK SF TV shows, ULTRAVIOLET with WHO alumnus Joe Aherne and... Idris Elba); John Simm (who's rather shot his bolt, there); and David Morrissey (who's currently filming the next WHO Christmas special, working out of a trailer marked "the other Doctor", curiously).
I'm sure there are a few more I've forgotten about. Any suggestions?