I discovered that yesterday too :)
Currently at home I am using XFCe4. Almost kinda glad to get a change.
I think the GNOME Team could take some pointers from XFCe. First off, my wife as a long time Windows User (before my conversion and at work now) and GNOME user, now using XFCe v4 found it much easier to use.
She browsed the Internet, Used e-mail, Typed a few Open-Office docs, played a few games, Instant Messaged, listened to music at the same time.
She literally had NO problems using XFCe4. None. Nada. Zippo. Zilch.
She likes XFCe v4 better than GNOME or KDE. This just boggled my mind.
I asked her if she got to do everything she wanted Last night and this morning. She said she noticed I upgraded and likes it MUCH better. She customized the crap out of it already. Rather than the default XFCE theme, she is using the RedHat Bluecurve, with WASP Icons and coloring. And a Nice Flowered background.
All without my help. BTW, she has a Stock GNOME2.x Desktop and she doesn't want to learn how to. XFCE was just easy.