This is what my desktop looks like for more than 90% of the time:

http://abstractnonsense.com/desktop.png

If emacs wasn't taking up the whole screen, I'd have a scrollbar running down the middle of the screen, which would be really visually distracting.

I used virtual desktops a lot back when I used Linux for my desktop os. They're great, and I'm sure I'll use them again when I upgrade from Tiger. But, for me at least, they're no substitute for maximization.