Re: VDPAU wont work on my 9600gt
Try disable Composite and Compiz. If that does not work, downgrade the nvidia module to something like 180.x or 190.x.
I have problems too with VDPAU even though my video card model is Geforce8 8400M GS. Since VDPAU is unstable for me and OpenGL makes my screen goes dark or blank for about 10 seconds, I use XVideo for video playback as a work around. Luckily H.264 codec is threaded, so I do not have to care too much for VDPAU.
IMHO, the 2xx.x nVidia modules are mainly for GT and Fermi only and not supposed to work for GeForce 8 and Geforce 9.
torgi, just a heads up, 290.10 crashes programs upon start up like Chromium and Xfce Terminal if using nVidia OpenGL libraries. The 290.10 crashes multiple programs on my setup when I tried using it.