I like screen savers. They are a way to make your Mac look cool when you are away from your desk and you want to show the awesome processing power of your computer. Of course if want to save power (especially on a laptop) these probably aren’t for you. Since they do soak up a lot of juice if you set the settings to maximum (which I did bye bye battery).
The first lot come from the well named site Really Slick Screensavers. There are three that I want to draw your attention to. Hyperspace, Helois and Euphoria. As you can see in the image below, they do look high speed, lots of movement, sprites, particles flying about the place. Great fun.
If you head to the downloads page you can find the download links to the screensavers.
The final screensaver which I would like to draw your attention to is the electricsheep screensaver. This site turned quite popular quite a while ago and is a really fun way to use your spare computing power. By using the screensaver you download a sheep and it will play as your screensaver. You then vote if you like the screensaver, if it become popular it mutates and lasts longer, similar to evolution in a way. Its cool and does produce some very good animations and screensavers.