All of the resorts look lovely at Christmas time, some just a little bit better. As a rule, I'd say that the decorations become more elaborate as you climb up the price scale. IE: Deluxe more elaborate than Moderates, and Moderates more than Values.
In regards to Gingerbread, my vote goes for the Grand Floridian. They erect a very large gingerbread house in the lobby. I have pictures of it on another PC. I'll find and post them...