If you want to take a closer look at XFCE in a live CD setting, you can download the newest Morphix "light GUI" CD from this Sourceforge location (~258MB ISO image). It runs XFCE 4.2.

(It's still beta and the biggest "gotcha" after a short run seems to be that it uses kernel 2.6.9 with the new "ub" USB block device but still wants to mount USB keys on /dev/sdax, and has no ubax nodes in /dev, so you can't save a persistent home on a USB key. Using USB peripherals is also problematic.)

Oh, after dinking around with GNOME for a while, my impression of it is that it has fewer "power tools" than KDE, and is geared more to new users (not trolling, just my opinion).