Comment 41 for bug 462349

I removed the launchpad ppa from /etc/apt/sources.list.d, and then did:
 sudo apt-get install xserver-xorg-video-intel=2:2.9.0-1ubuntu2

to reinstall the latest standard karmic driver. There's probably a better way to revert all of them (ati, nv, etc.) but intel's the only one my laptop needs :-).