Business Card Woes

I'm trying to redo my business cards. I am failing miserably. I want business cards that reflect my push towards vintage and antique hardware in my shop, but the first background I tried using was too busy and the second turned out ugly. I may have to photograph something specifically for the business cards. Poop.

Baby Got Back, and by "Baby" I mean "Business Cards"

Oh, my, god. Becky, look at her business cards.
They are so informative.
I like b-cards and I can not lie
You Etsians can't deny...

Business cards got backs.

If you spring for Moo cards, you're probably already using double-sided business cards with pretty pictures of whatever you sell on the back.
Sweet.
But there are so many other options for this second side, whether you use an international printing company, Etsy card maker, or make them yourself.
Business cards are small and easy to lose and throw away. The real trick is to make yours worth keeping around. Is there some piece of useful information a person would want to have that is also related to your shop? I've heard of size charts on the cards of clothing shops, recipes and metric conversions on all shops cooking-related, and rulers, tip charts, and calendars.
What do you have on the back of your business cards? What would you? What can you suggest for others? Please comment!