I'm not sure what's harder to believe - that in a little over a week, we'll see the latest Doctor Who Christmas special...or that in a little over a year, we'll see a regeneration story that will be David Tennant's last as the Doctor.
To be honest, I haven't really said anything about the news that Tennant will be leaving the role in 2010, just in time for Steven Moffat to take over as producer.
On the one hand, I've grown to really love Tennant's portrayal of the role, which I consider the "Davy Jones on espresso" Doctor. If his predecessor had the occasional flashes of humor through his battle-scarred persona, Tennant's Doctor was a mirror image, his seeming jocularity interrupted by flashes of rage, rudeness, intimidation, and regret. He's loved and lost (and regained and lost), he's become a father, dealt with the emotional aftermath of the Last Great Time War, force himself away from a trusted companion for her own safety...it's no wonder the Tenth Doctor is such a geek icon; he's handsome, emo, a snappy dresser, and quite handy with a sonic screwdriver. In short, I'll miss him when he's gone.
On the other hand, I'm glad that he's leaving on his own terms, that he's leaving before it "doesn't get to be fun anymore". His tour with the Royal Shakespeare Company as Hamlet has been rather interesting, with back injuries and some criticism (including a column by a man who has...an interesting name, shall we say). But Tennant has, if we believe that one full season of new equals two fo the classic series, done as much as the actor who played the role on television longest. Rather than leave with the audience booing him off - or even with the equivalent of a classic series Season 17 - Tennant is walking away from a show that he loves doing.
Those more cynical than I would suggest that this is for money, or to continue his Shakespeare work - but quite frankly, it's his decision, and although I'm sad to see him go, I am glad that he's walking away, and that he's not going to be treated like another of his predecessors.
And based on the few times I've seen him, I'm glad this man is in the running for the role.