As a small business owner, Christmas time isn't just about Santa Claus and presents. It's about giving. And by giving I mean giving holiday cards to your client base.
The power of a handwritten note should not be overlooked. Sending holiday cards to your clients, especially those that have retained your services over time, is a great way to remind them that you truly appreciate their business.
You don't have to write much. No gushing statements like, "Thank you for allowing me to eat and sleep in a bed." But a "Happy Holidays. I appreciate your business," suffices just nicely.
Also, you might want to think about getting generic secular cards (unless your client base is purely Christian organizations). You never know what someone's take on the whole "War on Christmas" thing will be. So find something with a snowman or a snowglobe or snow that says winter without saying Jesus.