Postal Money Orders (or even Wal-Mart MO's) are good, much better than checks.
If you want to avoid this in the future with BIN auctions, check off the "Paypal Payment Required Immediately" option. They won't be able to complete the BIN auction and "win" until they successfully pay for it.
I usually have that activated on any BIN listing, but also mention in the auction listing itself that I can take it off upon request if you would like to send an MO instead.
One of my biggest eBay irks is someone who wins a BIN auction, and then pays with Paypal 2 days later. That one is right above the person who "snipes" a BIN auction. It's been sitting there for 6 days and 23.5 hours, and you're buying it now???