I was reading a MacBytes C|net article about Sony wanting to make the iTunes-of-movie-downloads and ran across this article talking about Longhorn and why even once it's through development Microsoft may not be out of the water. Apple has updated their Mac OS almost annually and every time the users are salivating over it for months before it's release. Microsoft hasn't updated in over 4 years and their users are content to continue to use XP and simply not care. I guess that's what you get when you convince users that your product is good-enough, they feel it's good enough, and don't upgrade.
Longhorn has already survived several major delays, intense scrutiny from the industry and a radical redesign of its features.
But the toughest test for Microsoft's next release of Windows is still to come: Will anyone buy it?