You said for Xmas so I assume it is temporary? I'd do a white tablecloth but then pay close attention to runners, chargers, centerpieces, etc., to provide the color and texture to eliminate the "hospital" feeling. Another thought, and I don't know the age or temperament of your guests but you could get rolls of paper and use that as your table cover. Keep a runner (as you'll likely have a center seam) and then provide markers or crayons to "decorate". Also, if you have more than 1 dinner during the holidays, it's easy to replace with more paper. Additionally, any guest that wants to keep their scribble can cut out what they want for a memento!