
Quick Look is more than just image previews
The Quick Look feature in Mac OS X Lion is useful for previewing images, text files and websites. But you can also use it to quickly check the free space remaining on your hard drive.
Simply click on the Mac HD icon on the Desktop or in a Finder window and hit the spacebar.
Another quick way to check your free space is to turn on the Status Bar in Finder windows by visiting View>Show Status Bar (Command + /) and click on the Mac HD icon in the Finder window. The Status Bar at the bottom of the Finder window will display your free space.

My first problem is that I get a lot of email. My second problem is that I check my email throughout the day on my iPhone. And my third problem is that I often wish to delete emails without even reading them (thanks to spammers with no grasp of the English language, and horrible PR firms who can’t target the proper sites for their stories in the subject line).
Did you know that you can resize a Mac OS X Finder window when you’re in Column View to fit the widest folder or file name automatically? It’s a simple keyboard shortcut, and can save you a lot of scrolling and manual resizing. 
For example, if you have a box that measures 1.25 inches wide, but you really want it to be 1 3/8 inches wide, you can simply add +.125 to the existing 1.25 width measurement in the Control Panel input box and hit the Enter key (see image at right). While that seems trivial, the usefulness becomes apparent when you consider you can also use “/3” to divide the width by 3, or use “-” and a number to subtract an amount, or even “*” and a number to multiply the amount.