The Unofficial Apple Weblog: "Throughout the years, Mac OS X has definitely seen its share of changes. In these 7 years, OS X has been through 6 versions (7 if you include the first public beta version)." - Microsoft should consider releasing an update, not labeled as a Service Pack, every year. Something that improves on the Vista experience, be that performance, or a nice subtle UI improvement. It might make people feel a bit better about Vista given it hasn't been well received.