If you make an application go full-screen, it only does so within its capital-S Space. (Spaces being Leopard's native virtual-desktop thingum.)

So, when I'm using Windows in VMWare, I can have it go full-screen and, lo, the illusion that I am using a Windows computer is complete, as usual. But then I can hit Ctrl-→ and the entire Windows desktop exits stage left and I'm looking at a Mac desktop again. Ctrl-← brings me back to Windozistan.

That is very sexy.