Windows 8 keyboard shortcuts

Win + X   - context menu to access common features like Control Panel, Task Manager, File Explorer, Programs & Features, Run, Search etc
Win + E - Explorer
Win + F - search for only documents on your computer
Win + Q  - search for only apps on your computer
Win + W - search filter to show only settings
Win + ,    - view the Desktop
Win + C  - Charms (also shows Time & Date)
Win + P   - Projector settings

(Win - the Windows key)

work in progress...

(Update 21/Aug/12) Here's a much longer list from the Windows Team blog that makes the list I started redundant.

References -
Channel 9: Windows 8 Tips