1. Alt+Tab - this switches between open windows. Especially effective for hiding what you're doing from your boss. What?
2. Ctrl+C/Ctrl+V - copy and paste. One of the easiest ways to look like you know what you're doing.
3. Ctrl+Enter - inserts a page break. Page breaks can make your documents look clean and elegant.
4. Alt+FA - save as. Always Save As instead of Save so you remind yourself to change the document name, and place it in the proper location.
5. Ctrl+Alt+Delete - interrupts a function. In Windows, it brings up a cute little screen that can use to restart if your program locks up.
What are your faves?