The whole of the Great Battle was wonderful to watch. The White Witch, the Gryphons, the centaurs, the animals charging in, was fantastic.
However, what stood out for me was the unexpected "D&D Menagerie" around Aslan's cruci-er, sacrifice. Harpies, Cyclops, Minotaurs, Beast-men - I was crying for a D&D movie that featured all these things at this point. Every special effect needed for a kick-butt D&D movie exists out there, pre-modeled, and waiting for use, but it's spread though about half a dozen movies and three porduction companies.
Ah, well. If I never get my blockbuster-awesome D&D movie, I've got about six pieces to be insanely happy with, and add to my collection.
The realism to the Beaver interactions was beautiful to watch. As critical eye as I could, I couldn't find a flaw with the CGI in those scenes.