Last year, the carousel in the lobby of the Beach Club was taken down New Year's Day Evening, around 9 pm. By the morning, no evidence of Christmas existed around the resort, except for the poinsetta's in the garden's outside.
When we were there the past few years for the marathon, most of the decorations were still up for the marathon, but were down by Monday morning after the race. It's so cool seeing the Lights of Winter in Epcot during the race.