It's nice to see a whole family in silhouettes. I love seeing how dad's chin got passed on to little Johnny or how mom has the same profile as each of her daughters. We actually used silhouettes for our own holiday cards three years ago, which you can see above.
Last Christmas I made a card for a friend showing her family (the parents and their four children). I love how the personality of each child comes out in their silhouette. I was inspired by a piece of artwork which I saw in the article Martha Stewart Living ran about stylist Rebecca Robertson's home which shows mom + dad = child. (Rebecca was a stylist when I was an art director at Martha Stewart, and she is as lovely as she seems).
As a gift to my little sister for Christmas, I made a print of her little family and framed it in a simple black wooden frame. (I love these ones, and they are on sale right now!)