(I had just posted about this site in the 'favorite online site/service' and then happened to see this thread so thought I'd mention it here too in case people don't see my other one)
A friend of mine had sent me a neat free site in the summer that lets you upload your own photo and then add stuff to it like decorative frames, funny items, text, etc. and then you can save the image to your computer, email it to friends, or print it as a greeting card. I was excited to see they have Christmas related items as well, so I decided this would be great to make our custom Christmas card this year! The printed cards look great, and I'm going to use the email function to send it to people I'm not quite as close with (thought I'd help save a few trees! lol).
For those who just want something a little quicker (or something not involving a family/self picture) if you go to the 'cardz' section on the site, you can choose from tons of beautiful photographic cards (including some gorgeous Christmas ones) and then print them as a traditional card or send as eCards.
The best part is that the entire site is free!
Anyway, check it out: www.mirbit.com