This is a possibly crazy idea that I came up with: Make a GUI for an OS that looked pretty much like Aqua but was done in OpenGL instead of Quartz. Instead of 2d pictures you would have flat 3d objects with the pictures (icons, desktop backgrounds, etc...) put on as textures. This would allow you to shunt the entire GUI over to the graphics card, allowing the processor to do other things. I think it would be fast enough because Aqua is a lot less complex then Quake III and any recent Mac can handle QIII with ease. It would slow down 3d performance, but only if the GUI was showing while a 3d program was running, which is very rare (the only way I can think of it happening is when a 3d program is running in a window). Also, once the computers (or at least their graphics cards) got fast enough to handle it, you could easily add in "eye candy" like dynamic lighting, refraction, and reflection (personally I don't think eye candy is a good thing, but flexibility is always good). Another thing would be that windows in the background could actually be farther away, which could have some benefits. btw, I am aware of 3dOSX, but I think it's a rather clumsy way of doing it.