One of the really cool features of Mac's OS X is the docking bar/application launcher. A similar tool has been missing from all version of Windows, but there is a solution: RocketDock.
Rocketdock creates a docking bar upon which you can drag your most used applications for quick launch. This allows you to hide your less used icons for a cleaner desktop. RocketDock supports plugins as well, giving you the option of tweaking and extending its functionality to your heart's content.
RocketDock was created by a small company called Punk Labs, but don't let the name scare you. RocketDock is a genuinely useful addition to your everyday software.
Here is a video demonstrating how RocketDock works.