If one has a video card that supports DX hardware acceleration the resource hit will be offloaded to it, instead of one's CPU. For example, I have an ATI HD 2600 XT (256MB) and can run MilkDrop in Desktop mode with no hit on the CPU at all.
Interactive Fire
I've gone to Vista and totally forgotten about emulating the OSX look on Windows. If I want that now I'll just "Hackintosh" my new PC with an OSX build. Screenshot info at the link...