The thing is, when I'm doing anything but programming (web surfing, watching a DVD, playing music, etc.) I want the smooth, easy-to-use, pleasant-looking experience that I get on a Mac. I periodically try Unix window managers to see how they're doing, but they honestly always seem pretty clunky to me.

But let's say for a minute that I did go the Unix window manager route. What would you recommend if I wanted to have one "mode" where basically everything is stripped away (no menu bar, no windows, nothing -- just a shell), and another mode which was your standard GUI? It would have to be fast to switch between the two.