Windows 8 editions

Windows 8 editions
http://en.wikipedia.org/wiki/Windows_8

Features new to Windows 8
http://en.wikipedia.org/wiki/Features_new_to_Windows_8

Adding Start menu to Windows 8 Consumer Preview

Windows 8 Metro interface is good for tablet. But for desktop users, not much productivity gain.
You can add the good old Start menu to Windows 8 using this tool http://www.stardock.com/products/start8/