FreeBSD 9.0 is slated for sometime next summer if memory serves me
right, with PC-BSD 9.0 shortly thereafter.
I've already begun adding gnome / xfce4 / enlightenment to our 9.0
builds, and hope to start rolling snapshots based upon it sometime later
this fall. If you want to get a sneak preview of 9, feel free to join
our -testing mailing list to get notified when they are available:
http://lists.pcbsd.org/mailman/listinfo/testing
P.S, in the meantime on 8.1 you can install the ports for gnome2/xfce4,
logout of kdm and select gnome / xfce4 and that works reasonably well
here