Snow Leopard. Nothing new about the date and price from what we heard at WWDC this year, it's still listed for September at $29. Five-user family pack is $49, Server version is $499, and you can bundle a single or five-user pack with iWork and iLife for $169 and $229, respectively. We don't anticipate the OS being in short supply come launch, but if you need a peace of mind and Snow Leopard on day one, pull out your credit card and direct your browser Amazon's way.
[Thanks, Luis M]