http://gigaom.com/2012/02/28/why-windows-8-is-microsofts-mos...
FTA: "Windows XP was an updated but essentially similar experience to Windows 95, Windows Vista was an attempt to correct XP’s security issues but turned into a joke of its own, and Windows 7 was what Vista should have been yet failed to inspire."
XP was a pretty huge deal to anyone who wasn't already running Windows 2000 (which is almost everyone). It was the first consumer release built on the NT kernel and was incredibly more stable than previous consumer Windows releases. It may be hard to remember at this point, but XP was a huge game changer for the average user... a brave new world where a Windows app could crash without bringing down the whole OS to a blue screen!
I don't really get the Windows 7 slight. Windows 7 was a huge success, both in terms of actual adoption and critical praise.
I also found the lack of mention of Microsoft's very successful 64-bit transition (IMO this is a very undervalued aspect of Vista, though Windows 7 carried it forward to the larger masses) a huge oversight here.