Betas of these operating systems have been released recently, under the codename Intrepid Ibex. With lots of new features planted and thousands of bugs fixed. They offer the new exiting background, the latest desktop environments and the latest applications. They are available for downloads via their websites or upgrade by following the instructions.
Ubuntu haven’t released its latest desktop screenshot yet.
New desktop environments offers better navigation, more features, more bugs fixed and more stylish looking.
Gnome 2.24: http://live.gnome.org/TwoPointTwentythree/
KDE 4.1: http://kde.org/announcements/4.1/