Aeon costs $30 but is WELL WORTH it IMHO, it's gorgeous.) (The same author's G-Force was licensed to be the default visualizer in iTunes, until it was replaced by Magnetosphere. Aeon - this is actually an iTunes visualizer, but it comes with a screensaver, as well.I think I used to have more of these installed, not sure if I removed them because I got tired of them or because the OSX ports quit working. Several of the Really Slick Screensavers - Helios, Hyperspace, and Microcosm.Full Color Bossa - pretty colors, dreamy images, and the words for these colors in all kinds of languages (same guy as Hotel Gadget, he has one or two other screensavers that I don't use.).
Hotel Gadget - a dreamy trip through an endless hotel built by Surrealists.Electric Sheep - crazy fractals, collaboratively computed by computers running the program.