Windows 7 beta has came with lots of new shortcut keys, checkout below :


General

Win+Up	Maximize
Win+Down	Restore / Minimize
Win+Left	Snap to left
Win+Right	Snap to right
Win+Shift+Left	Jump to left monitor
Win+Shift+Right	Jump to right monitor
Win+Home	Minimize / Restore all other windows
Win+T	Focus the first taskbar entry Pressing again will cycle through them, you can can arrow around. Win+Shift+T cycles backwards.
Win+Space	Peek at the desktop
Win+G	Bring gadgets to the top of the Z-order
Win+P	External display options (mirror, extend desktop, etc)
Win+X	Mobility Center (same as Vista, but still handy!)
Win+# (# = a number key)	Launches a new instance of the application in the Nth slot on the taskbar. Example: Win+1 launches first pinned app, Win+2 launches second, etc.
Win + + Win + - (plus or minus key)	Zoom in or out.

Windows Explorer

Alt+P

Show/hide Preview Pane

Taskbar modifiers

Shift + Click on icon	Open a new instance
Middle click on icon	Open a new instance
Ctrl + Shift + Click on icon	Open a new instance with Admin privileges
Shift + Right-click on icon	Show window menu (Restore / Minimize / Move / etc) Note: Normally you can just right-click on the window thumbnail to get this menu
Shift + Right-click on grouped icon	Menu with Restore All / Minimize All / Close All, etc.
Ctrl + Click on grouped icon	Cycle between the windows (or tabs) in the group

Click For more Keyboard shortkeys