1. name
2. Classification (only 1 unless you're a writer/director. There are a few other exceptions. The point is, if you write a list of different things you do, you will be seen as a jack of all trades instead of an expert who can be trusted. If you do various jobs, get separate business cards for each classification).
3. phone number
4. email address
5. website address (if you have one)
6. YES a PO Box address is fine. I do NOT recommend home addresses!
If you have a graphic for your branding, that's great.
NOTE: leave white space for people to write notes about you. If you have a two sided card, be sure one side is matte finish so people can write on it without a Sharpie.
For more tips and articles by top entertainment industry career coach, The Greenlight Coach, visit www.thegreenlightcoachblog.com