I don't know how, but I've bumbled into a new (to me anyway) Compiz feature, a Coverflow-like ability to view multiple windows on a desktop. I installed KSnapshot in order to get a delayed screenshot of the effect, shown below.
Note the black bar running horizontally across the center of the image. This is an artifact of KSnapshot. It's not a part of the desktop. The effect is triggered by the key combination [Windows][Tab], or [Command][Tab] on the Apple keyboard. When you release the [Window] key on the keyboard then the window in the center is the upper window on the desktop. Very very cool. This is a Compiz feature worth having enabled. And the movement is very smooth, tight, professional, and fast without the crazy wobbles that first afflicted Compiz. And to think all this is running on a slow (1.8GHz) 32-bit Athlon XP with only 512MB of DRAM.
I am properly impressed!
It's available under the CompizConfig Settings Manager (ccsm), which you have to install via synaptic. The specific effect is Shift Switcher under Window Management.