why nvidia installer sucks
17:40 <dpkg> nvidia-installer works fine for you today, granted.  Let's say tomorrow Xorg is updated -- the nvidia driver will break.  If you try to uninstall nvidia (nvidia-installer --uninstall), then you break Xorg badly.  
nvidia-installer overwrites files at random, and has NO CONCEPT of package management.  We recommend against using it based on extensive experience.  USE THE DEBIAN PACKAGES.  Ask me about <nvidia>.