Heee.
The Doctor Who fandom is pretty much my "home fandom." Many a countless night has been spent with an audio drama or an old Doctor episode or something similar.
It's a very interesting character and concept, and I like how the show has tended to be very sensitive to world events and yet still maintain an "above it all" attitude and appearance.
I for one like what I've seen of Matt Smith, and think he's going to be an excellent Doctor. I suspect we'll see a companion who might be older than Matt.
Steven Moffat, the show-runner, is probably going to twist the show a little darker, much like the 1970s episodes.
One thing to understand about the show is that it is based on change. Every new Doctor is a new refresh, that takes the story in a new direction. There are some things that remain constant about the Doctor, namely that he doesn't really mention religion, he tends to be more of a humanist character (ironic since he's not human) , and he always tends to give the bad guy/monster/etc a choice.
But who knows. Eccleston to Tennant brought about a more hands on Doctor, and it looks like that trend might go even deeper with #11. Funny thing is, over on the Doctor Who forums and endless podcasts, we're already speculating on who #12 may be.