And I've got to say.....
BRAVO MR. MOFFAT!!
In his first season as show runner, Steven Moffat has managed to craft a true story arc. All thirteen episodes manage to both stand on their own as individual stories and at the same time loop around to create a coherent whole... and make sense.
He also finally took real advantage of having a main character who was a time traveler and actually played with time -- stretching things, bending things, making your brain hurt... it was all good.
All of the characters end up in a different place than where they started. All grow and change -- even the Doctor himself... in a way. The whole thing tugs hard on the heartstrings throughout and it's lovely.
Also, I have to say it. David Tennant is a fine actor, really he is, but Matt Smith just pwned him. Seriously. Tennant's dramatic regeneration scene doesn't hold a candle to Smith's final scene with little Amelia Pond... and it's not even a regeneration scene! Smith is, and has been, brilliant throughout the series. His style tending toward more subdued as he allows his expressive face and his eyes to tell most of the story. And for all that I hated the catch phrase "Geronimo" and was glad when it was seemingly dropped it actually nearly brings a tear to the eye when it reappears here.
I could say more but then that would be spoiling it.
Onward and upward from here!