I have very beatiful desktops, when i use my X11 windowing system. All of the beauty aspects are set via the X Resource Database, or XRDB. These are on display because they are very beautiful and practical, and because discussion about them rises every now and the, especially on an Emacs-related IRC-channel.

very nice, brownish desktop (48KB, 1152x864)
quite nice greenish blue desktop, which makes one think of hospitals (116KB, 1400x1050)