Mark Shuttleworth on his blog this week explained why Connonical are going to not only use their own window manager but also a replacement for the traditional X.org windowing system.  The article does a pretty good job of explaining his points.  He is a little lacking on hardcore details.  However it helped us clear up what  they were thinking.  Remember that no matter what if you don’t like their choice you can always switch yourself back to Gnome and/or KDE.