Well i prefer KDE 3.5 without compiz or any desktop effect (like with KDE 4). I sometimes even disabled composite in xorg.conf to get vdpau playback absolutely smooth, but that improved with newer drivers that you don't need to do that usually. 2d is really fast then too. But you can not even use something like vdpau on fglrx yet - or say some chosen ones can, the rest can't.