This year I am wearing a costume that I've built myself over the last 10 years. I usually wear it every other year since its such a production...
It is a cat that is loosely based on Mr. Mistoffeleese from the musical cats.
It is a black costume with black fur cuffs on my calves and forearms, a white fur chest piece, and a furry black tail with a white tip. I also wear a full face latex prosthetic, and full face makeup that takes me about 2 hours to complete. I also have a wig that I have added hair tracks to, cut, and styled myself (beauty school dropout!)
The kicker is that any piece of fur that is on my body has miniature, battery operated, Christmas villiage lights sewn in. The fur pieces lights shine through the fur when turned on. I have a total of FIVE battery packs on me at all times, and usually have to carry around a supply bag of touch up makeup and extra AA batteries.
If you've never seen the musical "Cats", here is the clip of Mr. Mistoffelees.
Here is a picture of me in a costume contest at work in 2004.... (this was a quick application, and you can't get the full effect in the daylight.)