Gnome desktop may update itself correctly, but you might have to re-install if it goes wrong. Just to be clear - you'll end up with the new-style Gnome 3 desktop, not the old style Gnome 2, with a top and bottom toolbar. That is what you want isn't it?
Steve
Hunting around, one of the other distros has Gnome 3 behaving like Gnome 2 which would be exactly what I want if I made the switch. Although if that's not possible 'n' years down the line, I'd be prepared to look at KDE. Anything but Unity.
Bev.