I agree that a nuke and pave is a good way to clean house. Yet, you cannot put a timeline on lost data or reinstalling applications, locating serial numbers, and recreating preferences, downloading all your codecs, unzippers, virtual drive apps, audio and adobe plug-ins, etc... Each takes valuable time to install and configure. I liked the idea of the black edition of XP with all the essential apps installed with the OS.
Microsoft needs to make data migration easier. I couldn't get XP to Windows 7 data migration to work properly and how do you know all that you need until you need it and it's gone. I had good experiences with Windows 7 over Vista.