I don't particularly like crisp, buttery cookies with frosting on them. I feel like the sugary coating takes something away from the simplicity of that type of cookie. In other words, if it's a good butter cookie, I don't want to disguise it with icing. But Christmas cookies deserve to be decorated as much as the tree and there is only so much that one can do with sprinkles alone (which are, incidentally, a fine addition to butter cookies). Frosting can allow you to be a lot more creative. Christmas cookies just want to be frosted.
I like to use simple sugar icing for frosting cookies, since it's not as rich or gooey as a buttercream, but still adds a nice, sugary taste. It is also easy to control the consistency of, so I can make it thin, for flooding large areas, or stiff, to draw the details. The frosted cookies themselves should be soft but firm, neither too sweet nor too buttery and they have to stay fresh for a few days. Gingerbread cookies are a good choice and easy to decorate, but whiter cookies give you a bit more color versatility, as well as less pressure to make ony gingerbread men.
Made with buttermilk, these cookies are soft and stay moist and fresh tasting for several days without getting too cakey or stale. They have a light vanilla flavor with a subtle tang from the buttermilk. The dough can be rerolled once or twice and holds it's shape well in the oven, though it does puff up a bit. The dough is sticky when it isn't cole, so be sure to have the dough well-chilled and your work surface floured. And the most crucial point? They hold up well to decorating and actually taste much better with the icing and sprinkles.
I'm already making another batch. After all, it's still a few days until Christmas and, while these will stay fresh until then, I don't expect them to last that long.