Here is a SHORT list of Windows 8 features you might/should care about:
A new authentication system lets uses draw their own custom patern on the (touch) screen as an alternative to using a password.
Windows To Go lets you run Windows 8 from a USB stick
Windows 8 will work on an ARM chip (i.e. Cell phone chip) (see video below)
Win8 supports using your Live/Hotmail/Passport account for local authenication
If you have more than one screen you use different background wallpapers for each screen
Windows Reset will wipe your PC back to fresh install state (i.e. clean the OS and dump apps and data)
Windows Refresh will replace system files with fresh ones and keep all your data and programs
Windows 8 has a new service start up type called ON DEMAND which allows Windows to boot much faster and use less memory because few programs startup on boot
Windows Explorer uses the Office 2007/10 Ribbon Interface
Windows 8 uses the new “Metro” interface which involves tiles rather than a Start Button like, Windows Mobile 7
ISO’s can be mounted like hard drives
Task Manager has been seriously improved with a much simplified default view for Ending Tasks, and an advanced view which now displays much more information in a a much clearer format. I could put up screen shots but THIS GUY already did a pretty good job.
Sick of Adobe Acrobat… good you don’t need it anymore because a PDF viewer is built into Windows 8
There is a Windows Store built in for buying apps directly from a trusted source
Windows 8 Server supports live syncing to a replica server with HyperV virtualization WITHOUT requiring Windows clustering services (see the bottom video)