We all know that we can keep regularly used programs ready for action in the OS X Dock or the Windows taskbar, but there are some great programs available that let you quickly launch anything on your system just by typing in a name.
On OS X, I use Alfred, a free, slick and simple launcher that you can pop up with the tap of a key, and then launch apps or do quick maths, or a host of other functions.
Another popular and very powerful option for Mac is Quicksilver.
On Windows, one of the standout options is Launchy, which is also available on OS X and Linux. It costs $3, and let's you type to launch apps, songs, documents and more.
If you like keyboard shortcuts, a quick launcher is a life changer.