I love Goetz Alsmann's CD, Winterwunderwelt (Winter Wonderland). It's a combination of Christmas songs you know and traditional German Christmas songs. Done up in lounge-singer style. Here's Lass Uns Froh und Munter Sein. (Let's Be Happy and Cheerful)
Many, many thanks to Julia for posting an Alsmann song on her blog last year. I was hooked. Immediately!