Screen Savers (403 programs)
Pros: Free screen saver mode. Great looking 3D models. Lots of performance optimizations.
Cons: Live wallpaper is a paid feature. Resource hog.
Pros: An original way to have a clock on your screen while you're away from the PC.
Cons: You can't turn music off.
Pros: Blends horror and comedy to great effect. Spooky soundtrack. Superb 3D graphics and slick animation.
Cons: Don't download if you're under 18 or prone to heart attacks.
Pros: Live blog activity mapped on a rotating 3D globe. Visually engaging and relaxing to watch. Lightweight and free to use. Runs automatically when system is idle.
Cons: No customization or content control. May not work on modern Windows without tweaks.