On top of what was discussed here, the most important message to convey via a practical title is:
a) did you started the company - e.g. Founder, Co-Founder
b) what's your key role (whom you make most of the decisions as) - e.g. CEO, COO, Business Development, Product, Marketing

There will be drawbacks when your audience are not sure what you do by reading your title, e.g. Chief Rainmaker, Chief Problem Solver... <- bad examples