I think you've got much better choices than either of those two, although I admit that I can't speak for Whiteface. I've never been there. All I know is that Killington blows unless your priority is partying. I know lots of people will disagree with me, but they tend to be New Yorkers, for whom Killington seems to be some sort of Mecca. If you want a real big-mountain experience, there is Sugarbush, Sunday River, Stowe and Jay Peak (the last two are my faves, while Sugarbush's two separate mountains for one ticket are pretty sweet, too).
I do agree that at the rate we're going, you'll be hard pressed to find a fully open mountain by Dec 16th, but you never know.
Last edited by surfinsnow; 11-26-2011 at 08:56 AM.