How fun. We went Dec 06 the 10-19 and it was perfect. Here are some hopefully helpful tips:
1. wrap any Christmas gifts BEFORE you leave so you are not freaking out when you return
2. Disney Christmas fun: Candlelight Processional,
MVMCP, Osbourne Lights, Epcot Tree lighting, Santa stories in World Showcase in Epcot, Resort decorations (everything Gingerbread)
3. Your kids (heck, maybe even all of you) may enjoy wearing a funky Christmas hat while you are there -- there were many fun, clever hats, like Christmas tree w/blinking lights, snowman mickey hats, Stitch/Tigger Santa type hats, etc. If this sounds fun, plan to purchase when you arrive, so you can wear it your entire trip (when you get home, you will wonder what you were thinking).
4. Book ADRs, but not so many that your schedule becomes about being somewhere at a certain time just to eat.
5. Work in all of the other Disney fun stuff too, and don't forget to relax. Get a good guidebook to get a good background knowledge about the parks, resorts, downtown Disney, and all that they offer. I think the Unofficial Guidebook is very comprehensive and has accurate, concise ride descriptions.
Peruse these boards for great info.
You will have a wonderful time planning this trip. Is it a surprise?