I agree! That is exactly what we just got back from doing, and it was so cool to see WDW during the holidays!
In addition to everything on the previous poster's list, all of which we did and loved, I would add going around to all the WDW resorts and seeing how they uniquely decorate each one. We had a blast!
We stayed two weeks with a weekend away at the Gulf Coast beaches, and it was also cool to see how Sanibel & Captiva islands celebrate the holidays.
Another "small town celebration" we discovered was in Winter Park, where we took that boat tour and they have the Tiffany/Maxfield Parrish museum. They bring out and illuminate the priceless Tiffany windows at a Bach-choir nighttime celebration in their Central Park to kick off their holiday season celebrations. It was cool!
We also toured the nearby Leu Gardens, where their house (a very interesting historical tour) was also decorated for Christmas.
Hm, I wonder if we'd made it to Gatorland if they were decorated for the holidays?
Due to the seasonal weather, we had the best time ever at the AK park, as the animals were actually active, and it wasn't like being in a broiler. They also had carolers.
Let me know if you have any questions.
Cheers