Look at the hundreds of business cards in your stash for examples. Most all of the ones I have say "Owner" unless they are financial/real estate agents in which case they get some watered down name like, agent or account manager.
If you have to explain what you do through a title on your business card, your business card is not complete. Not saying that having a title is a bad thing - just saying that you should focus on the complete package. Owner conveys a good message of understanding that you know what you're doing or at least are the person with all the connections to getting things done. Drywallrob makes a good point about freebies, but it's just as easy to say no or transform it into a "I'll give you this great price" conversation.
In my opinion, if you want to get elaborate with your title beyond Owner, do something creative that spawns conversation. Bad Ass Mother Fucker is a good (yet extreme) example. Pick a title for an ice breaker. Apple stores use "Genius". Try, Know It All, Expert, Smart Guy/Girl, Level 85 Warlock - whatever.
