I would love to be able to send this year's Christmas cards using the Guernsey Christmas stamps, which were designed by school children, and are shaped like ornaments - click the image for a larger view.
I really like the Magi stamps this year. I don't think any other country has quite the selection of Christmas/holiday/winter stamps that the USA has - this link takes you to the holiday stamps available this year. USPS also likes to hoard past Christmas issues, which is great. I just wish they had better stamps at other times of year (like Halloween!)