On Windows, you have Launchy, a small application that saves your time by just type in the application name rather than just go through Windows Start Menu to do the searching. Same on Linux, there is such similar feature software called GNOME Do.

Besides the basic function, GNOME Do has awesome plugins which allows you to send email, instant messenger, play music, search the web and more. GNOME Do not only for GNOME, it also works on KDE!