We were there in early December of 2005 and the crowds weren't too crazy. It was a nice time to be in the World b/c we saw all of the Holiday decorations, such as the the various trees at MK, Epcot, the resorts, etc and the Osborne family lights at MGM without dealing with unbarable crowds! I'm not 100% on what the crowds will be like when you are planning your trip, but I know that the crowds became thicker at the parks toward the end of our trip, we were there Dec. 5th through the 14th of 2005. All I know is that December and the Holiday Season is a great time to be at WDW and I'm sure you will have a wonderful time regardless of the crowds!