The term "founder" describes your relationship to the history of the business. Page and Brin will always be Google's founders. The term "CEO" is about your position in the current organization's hierarchy. Some founders will be CEOs, at least for a while.

Titles are the easy way for outsiders to understand how to connect with your organization. So if you're the head, just use the title CEO unless you have some strong reason not to. That way people will know to come to you with CEO-ish things. There's no harm in putting "founder" on your business cards as well. E.g., "Founder / CEO" or "CEO & Founder". But things like "CTO & Founder" are also legitimate, so don't go with "Founder" alone, or people will be left wondering which things they should contact you directly about.