SHIFT-Enter – Gives you a line feed as opposed to Enter which gives a carriage return.  This is useful when you want a new line on a bulleted list (without it adding another bullet) or beginning a new line without ending a paragraph.  A rough HTML analogue would be Enter=<p> where SHIFT-Enter=<br>

CTRL-ALT-PrintScreen – takes a screen shot of just that particular application.  Great for browser screenshots.  As a bonus you can now paste copied screenshots directly into a GMail message.

SHIFT-CTRL-V – pastes your text with formatting removed.  This is particularly useful when copying text from web pages into e-mails where you don’t want to preempt the existing formatting.  Unfortunately this shortcut doesn’t work in a lot of Microsoft programs.

Any letter inside of a folder – click inside of a folder and type any letter and the file starting with that letter will get selected

SHIFT-CTRL-T (in browser) – brings back tab you just closed