Windows Vista is the Windows Me of the 21st Century
I earlier compared Windows Vista to the Sony PS3 (expensive and not selling well). More recently, I've been thinking of Windows Vista and Windows XP to be the current analog to the Windows Me and Windows 98 SE relationship. Windows Me was a disasterous release that followed the stable and well supported Windows 98 SE (Second Edition). Vista follows the stable and well supported XP. I'm apparently not alone in this general line of thought as exhibited by commentary over on CNet.
Why Microsoft must abandon Vista to save itself
Speaking of Windows 98SE, I wrote a somewhat tongue-in-cheek item over on the O'Reilly Network titled...
Microsoft should release Windows 98 SE as Open Source
These days, I think that while it is still unlikely to happen, I think Windows would see a resurgence if Windows 98 SE's code were released as Open Source to allow the vast number of talented developers out there to clean it up, secure it, and enhance it.