After playing around with my drivers, my Nouveau driver no longer seems to support 3D acceleration: Compiz effects are gone, as are 3D gaming capabilities.
Nouveau is still doing something correctly in 2D (e.g. the 1600x900 resolution is still correct, as compared to no NVIDIA driver at all, when it's 1280x768 instead).
How do I fix this without reinstall Ubuntu for the billionth time?
xorg.conf's that I've tried:
This (which was the original):
Section "Device" Identifier "Default Device" Driver "nouveau" EndSection
Other things I've tried:
sudo apt-get purge xserver-xorg-video-nouveau --remove
sudo apt-get install xserver-xorg-video-nouveau --reinstall
Uninstalling/reinstalling through Additional Drivers