I've got my eye on this Silk Steamers Cami. It seems like such a versatile piece for the holidays.
You could wear it with swingy black trousers and heels or really dress it up with a skirt and one or more of these Club Monaco necklaces:
Generally, I find holiday dressing pretty stressful, so it's probably not a bad idea to line up a few party wear options. Fortunately, this year, I have an ace-in-the-hole dress: