KDE exclusively, Sabayon as primary OS. KDE nearly lost me with the jump from 3.5 to 4.0. Tried Gnome for a few weeks... but missed KDE's flexibility. Switched back to KDE and road it out. Now at 4.5, I rarely experience issues with it. AND I run Compiz and emerald to boot... I love showing off Sabayon with KDE to my Windows buddies! Watching their jaw drop is nearly as satisfying as the full Sabayon experience itself... !