Christmas decorations are the best part about going during that time of year. You will love the way the castle is lit up, Osborne Lights at Hollywood Studios, the deluxe resorts have very cool chocolate displays, Christmas party at MK, Candlelight Processional at Epcot.....just to name a few.
As for dinner at a resort, I think they all provide some sort of traditional fare with what they usually offer. We tried Cape May last year because we didn't want to worry about being in a park and they had turkey and potatoes, etc. along with their typical seafood.
Have a great time, you'll love it.