Okay, I know that I am tempting fate with this one, but any linux form that is worth its salt has one; and we're already half-way there with the screen shots gallery.
So, which window manager do you use? I have KDE 3.2, and fluxbox on my desktop, I have used GNOME but I didn't really take to it in a big way, and I use fluxbox on my laptop to keep things fast - which I really love but I still need to get the icons working right!!
Also, if you have any great links to themes and wallpapers (not the obvious ones like the bob-standard kde & gnome site) post them so that the rest of us can have a gander!!