Really, the best possible answer would depend, greatly, on how you think you'd like to spend much of your vacation time that January. Being in a monorail resort (or WL or FW) gives you easier access to all the other MK resorts and their amenities. Staying in one of the Epcot resorts also gives you walkable access to 4 other resorts (including their restaurants and lounges), the Boardwalk district for later-night fun (again, many of the parks close early during January). Animal Kingdom Lodge is slightly more remote, so you're not close to any other action, but man is that resort bee-yoo-tee-ful, and you've got 3 full service restaurants plus a food court and 2 big pool areas. Saratoga gets you walking distance to DTD and all the restaurants and bars there, plus movies, Cirque, and if either you likes shopping, you're golden. Not to mention on site you'll find 2 big pools, 4 quiet pools, a restaurant and food court, a great spa, and easy access to golfing.
None of this even mentions the moderates, which might have smaller rooms, or perhaps fewer onsite amenities and no easy access to other resorts. Of course, if you have your own car, this will render much of the decision making process moot because you can go wherever you want whenever you want.
So...that probably doesn't help at all. best thing to do is figure out what you'll be doing most of the time (on vacation with no kids, the right answer to that question means it won't make a lick of difference WHERE the room is, as you'll rarely be leaving it wink wink nudge nudge).