Hi Christina,
My family spent Christmas and New Year at Walt Disney World last year and had a truly amazing time!
We actually visited Epcot on New Years Eve and felt that this was a good choice as this park in particular does seem to be able to cope with large crowds better than others, mainly down to its size.
My son who was 7 years old at the time, did not manage to stay awake to see the New Year in but we did see the earlier showing of the special version of IllumiNations: Reflections of Earth which was absolutely fantastic!
Special fireworks shows are usually held at the Magic Kingdom, Epcot and Disney's Hollywood Studios on New Years Eve so it really depends on your preference.
I would recommend that you keep checking the
Disney Parks Blog for more information on New Years Eve happenings at Walt Disney World.
I hope that this information has been of help and wish you a magical trip filled with memories which will last a lifetime!