I went in december of 1998. Its the best time to go. We went on dec. 3-7. It was not crowded AT ALL. We practically walked on every ride. MK is so pretty during dec. They have all christmas decorations and everythinjg. Also, MK has Mickey's Very MErry Christmas Party, which is fantastic. In MGM, the osborne lights are a MUST SEE. There r sOoOoOoO many lights! In Epcot, the candlelight procession is really good, too.
I hope I helped!