Use that Spacebar!

If you want to know how much space is left on your Mac hard drive highlight the drive (either the icon on your desk top or in the devices area of your finder) Then simply press the space bar. The space bar invokes Quick Look and it also works on other files that reside on your computer. For instance if you highlight a graphic file on your desktop and press the spacebar it will give you a quick preview without having to actually open the file. If you highlight a word document, you get a preview of that document without having to actually open tin in Word. This can be a real timesaver when you are cleaning out your hard drive!