Looking at some of the replies above, I am not sure if we were at the same WDW that they were at.
We were there last year from 12/17 thru 12/26. Every ride, except Soarin, in every park, right up to 12/24 was a walk-on or no more than a 5 to 10 minute wait. The only crowds we found the entire week were in MK on Christmas morning, so we left there and later in the day went to MGM. MGM was pretty empty that night. Fantasmic was only 1/3 filled on christmas night.
This is such a great time to be at WDW that we will be there again this year from 12/21 thru 12/25.