Every year the US Postal Service brings out a range of stamps for the holiday season. There are generally a variety of religious stamps, and then there are one or two series that are non-religious. This year they have cookies (which are apparently left over from last year):
I’m a huge fan of the snowflakes. They’re beautiful, and they’re real photos. The images used come out of the Snowflake Lab at Caltech, where they grow snowflakes under controlled conditions. The Snowflake Lab’s web page is definitely worth a visit. They have beautiful images (which are available as wallpaper for your computer) and movies of snowflakes/snowcrytals growing, as well as lots of easily accessible information.