1) Use Paypal! - Paypal offers up to $5,000 (may be a little less) buyer protection. If the user doesn't have Paypal, the user doesn't get my money - that simple and no questions asked.
I totally agree with using Paypal for all trading transactions. Paypal is NOT a great service except charging us $$$$$ but at least you can claim your money back in case we have to deal with some bad guys out there.