Of course, I'd love 10 or 20 years of Matt Smith, perhaps rendering the issue moot.
I voted for the fourth option, as it most closely approximates my current wishes.
Though the boy Smith is great as the Doctor, the show would probably suffer from any one actor becoming synonymous with the role for very long.
It's tempting to say "Just establish that he was given more regens in the Time War" or somesuch. However, there is a certain attraction to sticking to the limit. Almost every story since the show began in 1963 has involved death in some way; it's as if the Grim Reaper is a nodding acquaintance of the Doctor. There comes a time when maybe they should stop dancing around each other and just get it on.
On a more serious note, I think that
Doctor Who has entered the public consciousness in the same way as Robin Hood or Arthurian Legend. In the case of the latter there are conflicting versions of the popular myth; eg Excalibur being the "sword in the stone" versus the "lady in the lake" origin. By the same token, why not end
Doctor Who and have a new version of the mythology replace it at some stage? The time may be approaching when even the show's current incarnation may seem quaintly anachronistic. In the last few years we've seen a "remote locking" facility for the TARDIS and even the ability to open the doors with a snap of the fingers. With the advent of controllerless interaction such as with the Kinect, will the idea of a console become outdated in the next ten or so years? Will modern technology begin to catch up with the Doctor's ability to regenerate? It could be that a "final incarnation", if handled properly, will be a means of drawing a line under the show's history to date. This being
Doctor Who, the only barrier to a future revival would probably be the extinction of popular culture itself.
