I would second the WL, love their lobby area in general, but they do a great job with holiday theming.
In general, as you'd expect, you're going to see much better holiday theming at the deluxes. The moderates decorate too, but obviously their space is smaller. POR in 2010 had a tree in their rotunda area outside the check in as well as some garland by the registration desks. I don't know if the values theme at all.
I'm not sure the holiday decorating itself would be my deciding factor, especially since we like to visit all the deluxes anyway to see what they've done. Pretty much all the theming is in public areas, so anyone, including non resort guests can take it in.
Grand Floridean always has a life size gingerbread house that they erect in the lobby. I think either the BW or BC/YC will have some kind of chocolate sculptures on display, and all the deluxes have very nice themed trees in their lobbies. (actually, not sure about the Poly on that one).