First, look for a brand name manufacturer like Supermicro, AOpen, Abit, Tekram, Asus, Tyan, Intel, and so on. A strong brand name is like a contract between the manufacturer and the consumer ensuring the quality of the manufacturer's products. Brand name manufacturers move hundreds of thousands of boards, and you can be sure they want to keep their customers happy.
A brand name ensures the board's compatibility with other system components. With the sheer number of boards produced, compatibility issues, if any, are quickly found and resolved, usually with a BIOS update.
Corporate websites provide customers with flash BIOS updates, online documentation, and FAQs. Be sure to take a look at the manufacturer's website before buying a board. Always do a dejanews search of Usenet for compatibility issues before buying a specific board, especially if it's a next generation product. You can usually gauge how reliable a board is by looking at what everyone's saying about it. But what good is a name if they don't carry a model to support your CPU?