NOOOOOOOOOOOOOOOOOOOO!
Don't use the official nVidia installer, it breaks a lot of debian!
Do all this as root:
1. Open your /etc/apt/sources.list is whatever editor you want
2. On the end of both your main deb repo lines add " non-free contrib"
3. Save the file and run `apt-get update`
4. Run `apt-get install module-assistant nvidia-glx nvidia-settings`
5. Run `m-a a-i nvidia`
6. Run `echo nvidia >> /etc/modules"`
6. Run `dpkg-reconfigure xserver-xfree86` and select the nvidia driver
if you are running a debian stock kernel you will also need to download the apt package containing the kernel headers.
Also, build ur own kernels, debian stock kernels suck