After testing a few desktop environments (GNOME, KDE, Xfce) in CentOS 6.2, there was one thing that was missing in Xfce – the Compiz Desktop Effects. Very helpfull was ArchLinux forum.
I have opened the Xfce Settings Manager and then the Sessions and Startup. Next thing was to open the Autostart tab and add a new entry:
Name: Compiz Fusion
After that I restarted the X server.
If you don’t have the fusion-icon installed you could do that by doing this:
# yum install fusion-icon