Forgot to mention that as long as you go through PayPal and pay through Goods and Services, and not Personal/Gift, then you are at least covered under PayPal's buyer protection. I know a lot of us use Personal/Gift (myself included in that list) since I think we are all generally good people, but if you're worried, you can't be too safe.
Also, if you're really worried then ask that he send you a PayPal invoice and you'll have even further evidence in the issue of a dispute.
Also, although I do post, somewhat regularly, I don't post as often as I could. I learned long ago that the Search button is my friend. I'll usually only post a new thread if I honestly haven't found the answer after a significant effort.