My wife, two of our four children (daughter, 7 and son, 5), and I just returned from the 11/24/07 - 12/1/07 Eastern Caribbean Cruise aboard Disney Cruise Line's Magic. The ship was decked out in Christmas decorations. There was a lighting of the Christmas Tree ceremony with the characters complete with snow in the Atrium. Christmas music played in the hallways, it was great to get into the Christmas spirit even in 85 degree weather.
Overall, the cruise was good to great. My wife and I both agree that we WOULD NOT take this cruise without children (although that may seem obvious, there were many more folks on board without kids than either of us expected).
Note about Kids' Activities: our kids did not enjoy the children's activities. This was a bit disappointing, because my wife and I were looking forward to some alone time that never really materialized.