I migrated to OS X partly because of the huge hassles involved with using open source software on Windows, but also because of its looks. Apple's cold elegance is definitely preferable to Microsoft's slick, fake smile.
Ubuntu, however, is likely to be my new home. After having Ubuntu and the 3D wonders of Beryl demonstrated to me by Vancouver open source evangelist Scott Nelson, I was blown away. Linux is now not only free and functional, but is fun and looks great.
I've since set up my own Ubuntu workstation and have found that using Beryl offers benefits I'd never expected. Having virtual desktops mapped to a 3D cube simulates real world space and, for some reason, seeing the cube rotate while switching desktops helps reenforce my comprehension of navigation through conceptual space. There's also the benefit of "feel". Having windows that wobble and bend gives the desktop environment more of a sense of life, which is nice when one is spends one's days in it.