I did the update yesterday on my core and my MD. After killing X I did "apt-get remove nvidia-glx-260", edited out the content of nvidia-installer.sh, downloaded the 285-nvidia drivers from their website and installed them. I did have to struggle a bit, because at first I didn't do it properly and X wouldn't start up again. Actually I had to do it twice, but then it worked and I could get through the AV-Wizard