Early December is awesome!! It use to be one of the least crowded times to go, but cast members started telling everyone that and now it's a circus, but the crowds are still MUCH more manageable than during Thanksgiving, Christmas, or New Year's. My favorite Christmas activity is Holidays around the World at EPCOT and visiting the resorts. The Contemporary, Grand Floridian, Beach Club, and Boardwalk all have beautiful Gingerbread displays. All four of those resorts are monorail/boat and walking/boat accessible.
For resorts, I love Port Orleans and I'm partial to Riverside. I like that there's a large and diverse quick service option onsite. The rooms are split into Alligator Bayou and Magnolia Bend. I prefer the mansion-style building in Magnolia Bend. If you reserve a Royal guest room (themed after Princess and the Frog), it guarantees you a room in Magnolia Bend.
Regardless of which Port Orleans resort you choose, taking the boat to Downtown Disney is a must. The Sassagoula River is beautiful and the boat ride is such a nice change of pace from the bus.
The most important thing in touring WDW is to get to the parks early. Many attractions are "walk-on" first thing in the morning and the headliners will develop waits of an hour or more by mid-day. Take advantage of the FP+ system, especially for the following attractions. Schedule most of your fast passes for afternoon or evening to take the fullest advantage of both rope drop and FP+:
MK - Space, Splash, or Big Thunder Mountain; Meet Anna & Elsa; Seven Dwarfs Mine Train; Enchanted Tales with Belle
EPCOT - Soarin' (ride Test Track Single Rider)
Animal Kingdom - Expedition Everest, Kali River Rapids, Kilimanjaro Safaris (substitute Festival of the Lion King if you prefer)
Hollywood Studios - Toy Story Mania
Magic Kingdom has the most attractions and the most for which FP+ is useful. Considering spending more than one day there. EPCOT is also a good place to spend more than one day. Not because there's so much to do, but because of the sheer size of the park.
If you make your resort reservation within the next 3 weeks, your dining window will open up for your entire stay 180 days before your first day. (Otherwise you will only be able to reserve one day of dining at a time.) Use this to your advantage and book hard-to-get reservations like Be Our Guest or California Grill for the end of your stay. As for favorites, we steer clear of signature dining experiences for budgetary reasons, but my go-to table service dining choices are Cape May Cafe's seafood buffet at dinner (located at Beach Club resort--walking distance from EPCOT), Ohana (at Polynesian Resort--monorail from Magic Kingdom), and Garden Grill (inside the Land pavilion at EPCOT).
I agree completely with Figgy--the Unofficial Guide is awesome.