Windows users miss out on something Mac and Linux users have enjoyed for years: virtual desktop support. Virtual desktops create discrete desktop interfaces, letting you, say, maintain separate desktops for work, play, and communication tools, and switch between them at will. It's a great way to reduce clutter and keep like programs together.
Dexpot rocks not only because it's absolutely gratis for personal use, but also because it's packed with UI hints to remind you about your virtual desktops, and it's extremely customizable. Take some time to get acclimated to virtual desktops—they're a bit of a learned behavior—and you'll never be able to go back to the stock, solitary Windows desktop again.