Finally, finally, the BBC has released the first trailer with actual footage of the Day of the Doctor, and eee by gum does it look like we're in for some fun. Of course, the trailers always look good, that's their job, but I'm properly excited about this now. Smith and Tennant look to be having a grand old time together, though that serves as only more of a reminder of how close Eleven has become in characterisation to Ten, and why the Dozenth Doctor will need to go hard in another direction.
Now, for some analysis. I think, from all the shots of some very Gallifreyian architecture and fashion, and the prevalence of the Daleks, that the Time War will factor into the story. And that John Hurt's character is the Doctor that stops it, be he Eight, or be he a regeneration between Eight and Nine (which will technically make Capaldi the Baker's Dozenth Doctor, and as far as we officially know, his last regeneration). This trailer makes it look like Rose is instrumental in that decision, which might go a ways towards explaining why Nine and Ten were so obsessed with her. In fact, it might explain why Nine went looking for her in the first place (as it now suggests that their meeting was a coincidence).
But damn! Bits of the Time War, hats and spectacles, and and sonic screwdriver measuring contests! I really really want this not to be terrible.