The single-second shot of Capaldi's eyes - a bit gimmicky, but my favourite moment of the show. The Zygons were excellent as well, probably my favourite, and most scary monsters since The Silence.
As long as Gallifrey still being alive and well isn't touched too much by physically bringing the Time Lords into general storylines, I think the special has worked tremendously. It changes the way the Doctor is looked at, and he loses a bit of the air of mystery that he always has, but the unravelling of that mystery really made the episode.
Just watching the after-show on BBC3. One Direction: