http://www.webdesignerdepot.com/2010/06/how-to-design-you...
As web designers and developers, we often overlook printed marketing materials. But on occasion, they can come in very handy: at conferences, when we meet face-to-face with clients, or when we happen to run into someone we might want to do business with. Having business cards is a great way to promote yourself in the physical world.
Remember that famous scene where Christian Bale wigs out over a business card? This is basically the same thing. Just real. And not ultimately ironic.