Windows
Reverse Tabbing
So most people probably know they can tab through GUI's, and what not, but did you know you can go back too? Try it... Shift & Tab.Open an Application as an Adminstrator
Search for an app in the Start Menu and hit Ctrl & Shift & Enter.Open an Additional Application To What Is Already Open (Windows 8 Special)
So you already have an instance of Remote Desktop open. Want another without loading up the current instance? Then search for the app and hit Shift & Enter.Right Clicking
Ever wondered what the key on the bottom right of the keyboard is? The one between the Windows and Right Ctrl key? That's the menu key, and it behaves the same as if you right clicked the mouse on the currently selected item.
Task Manager
Ctrl & Shift & Escape... no need for Ctrl & Alt & Delete.Magnifier
Win Key & [+ Key (Addition)]Moving Windows
Align to the side of the window: Win Key & Left Arrow / Right ArrowMaximise/Minimise: Win Key & Up Arrow / Down Arrow
Settings Charms in Windows 8
Need the settings for the app? The power menu to shut down the PC? Adjust your volume? Find it here with Win Key & I
Browser
Chrome is my main browser, but as far as I'm aware, most other modern browsers support these shortcuts.
Switching Between Tabs
Ctrl & Number of the tabClosing Tabs
Ctrl & F4Reopen Last Tab
Ctrl & Shift & TJump to address bar
Alt & DWhile it was good fun, I actually use these shortcuts very frequently and they without a doubt increase my productivity.
In summary, I think the only thing I had trouble doing was modifying an image in Microsoft Paint (Win Key & R -> pbrush, by the way).