Mac OS X: If you ever do any advanced file browsing on the Mac, you probably spend a lot of time running terminal commands that show hidden files, force empty the trash, and more. Menu bar app DesktopUtility puts those functions just a click away.DesktopUtility is incredibly simple, but useful if you ever work with system files on your Mac. With just a few clicks in your menu bar you can show hidden files, force empty the trash, hide the Desktop, and show and hide the User Library folder (in Lion). Most of these you can do with Automator Services, of course, but you can't beat the convenience of a simple menu bar app that puts them at the ready (without sucking up resources).
DesktopUtility is a free download for Mac OS X systems running 10.6 and up.