GF hands down... Everything from the lobby decorations, to the landscaping touches, and of course the Gingerbread House! There's some great pics on the FAQ thread of Christmas time...
Thank You so much! Never been to WDW during Christmas.... soooo looking forward to it! My DH and I will be celebrating our birthdays and I want it to be the best trip ever!!
I personally hate the GF. The decorations are pretty enough, but it's all done in that over-the-top victorian style. The CR and Poly are more subtle for the most part, and that's more in my taste (and much less tacky).
Of course for Christmas my favorite by far is the WL. The theme of the resort just lends to that Christmas-y feeling.
I pick GF then, it is more themed than Poly (for the holidays) and there is a live band playing great carols, the roasted chestnuts in the front by valet parking, a hot toddy at the bar upstairs, the smell of the gingerbread house in the lobby..cannot go wrong!
While the Grand Floridian looks very nice at Christmas time, the lobby of the Royal Palm building can also be very busy with the Gingerbread House along with everyone wanting to visit it, choir groups that sing there and more. While you don't need to stay in Royal Palm it can sometimes be frustrating to move around.