I'm fairly sure Swan and Dolphin decorate for Christmas as well but I don't know when they put them up - probably no later than Thanksgiving weekend.
I've really liked CSR's decorations for moderate resorts (I'll see CBRs for the first time in a few weeks) and WLs for the deluxe resorts. If you get the chance, take time to travel around to diffferent resorts and check out their decor.
If you ever get the chance to do the Backstage Tour offered at WDW, they run you by the large warehouse where they store and make new decorations each year. Quite an impressive operation.