Hi Casey!
I'm so excited to hear that you're planning a return trip to Walt Disney World! Christmas is a wonderful and magical time to visit, and as you can imagine, a very popular destination for fellow travelers.
I absolutely love the convenience of a monorail resort, and my family truly loves
Disney's Contemporary Resort. Super convenient walking distance to Magic Kingdom (if you so choose), and the efficient and fun monorail.
If you're looking at a moderate level resort, check out
Disney's Port Orleans Resort - Riverside. We've stayed here many times, and love it more each time we stay! Beautiful grounds and great amenities.
As for Christmas Day, keep in mind that it will be busy, and Magic Kingdom will be the busiest of all the parks, so if you have your heart set on spending the day there, know to expect a crowd.
Christmas dinner is another item that will need to be squared away as soon as possible, because dining reservations on that day book very quickly, so make sure that you book that at your 180 day (from check-in) date. I personally love
California Grill, and love that it offers a beautiful view of Magic Kingdom, you can even enjoy the fireworks without the crowd. I think it'd be a great way to cap off the day.
Have a magical vacation!
Amanda