An LLC provides a good balance of operational simplicity and liability protection compared to sole proprietorships and corporations.

From a U.S. perspective, I would suggest keeping things simple: incorporate where you do business, until you have a reason to optimize your tax liabilities. Typically, this would be in your home country (and home state/province), to simplify paperwork. If you're in the U.S., don't bother with "off shore" incorporation since the IRS lays claim to worldwide earnings for U.S. persons/companies and it's on you to prove otherwise. For almost everyone else, the world is your tax oyster :)