The reason this episode is so steeped in the show's history is that the writer was Neil Gaiman, one of the more well-known users of mythology and world-building. He is most known for writing the Sandman series, as well as American Gods and Coraline (later adapted into a rather excellent movie). He has gone on record as saying that he knew what a Dalek was before he had ever heard anything of real world myth and legend of the Egyptians and Greeks, and you can tell how much knowledge he has accumulated about the show.
In my honest reviewing opinion, the highlights of the episode were the impressively nice Alan Rickman-alike voice of Michael Sheen (the sparkly effeminate leader of the Volturi from Twilight: New Moon), the rather spooky green-eyed Ood (somehow managing to look creepier than when their eyes were red), and the cute little touch at the end when Rory and Amy tell the Doctor that they don't want bunk-beds in their bedroom. The Doctor's naivety in this matter (or apparent naivety, anyway) is really heartwarming and funny. Special mention, however, must go to the line: "Biting's excellent. It's like kissing, only there's a winner." Only a genius of Gaiman's calibre could've come up with that, and I was so enamoured with the line that I immediately texted it to my girlfriend with the thought that she might appreciate it. (She did.)
Those are just my highlights of an already great episode. It somehow manages to be dark, happy and deeply informative all at the same time. There were some low points, as there are in everything (such as Rory dying. Again. They're turning it into a joke now.) but overall, it was a fantastic episode and absolutely worth seeing, and as soon as possible.