Cedric, thanks for the tip about purging xorg-edgers ppa. (ppa-purge didn't actually downgrade the packages, but I marked them all manually and downgraded them.) It worked, and I have the nvidia driver working properly on reboot. The only thing wrong that I can see is that Jockey says, "No proprietary drivers are in use on this system," and doesn't give the option to switch to a non-proprietary driver. Anyway, thanks very much for getting the nvidia driver packaged so quickly.
Cedric, thanks for the tip about purging xorg-edgers ppa. (ppa-purge didn't actually downgrade the packages, but I marked them all manually and downgraded them.) It worked, and I have the nvidia driver working properly on reboot. The only thing wrong that I can see is that Jockey says, "No proprietary drivers are in use on this system," and doesn't give the option to switch to a non-proprietary driver. Anyway, thanks very much for getting the nvidia driver packaged so quickly.