I'll throw in here -- I order business cards from American Stationery. They're inexpensive, on good stock, and they have cool fonts to choose from.
As for what goes on a card, I was skittish at first about putting my address on it (the first cards I had done had only my phone number and e-mail, but looked a little too spartan.) But I was at a writer's conference and discovered that most of my non-fiction brethren (including a Pulitzer winner) had their addresses on their cards. And that makes sense, because when you're out doing research, it's helpful to have a mailing address where people can send information if they can't e-mail it.
I struggled, too, with whether to put "writer" or anything like that on it. I ultimately decided to put a short slugline under my name -- though rather than saying "writer," it says "I write stuff," which is just casual enough to let me get away with it, IMO. I decided to do that, again, because when I'm out interviewing sources or researching, I can hand people my card and they don't pull it out again later and go, "Wait, who was this guy again?" And to answer a question from waaay up above, no, I do not have my agent's name on it -- but I do have my website, where people can go to FIND my representation, should they so desire.
Your mileage may vary, of course.