I’m currently running Debian testing on my laptop, it’s a Dell Latitude E6510 with an Nvidia video card. Here’s what I did to get it working, it was less painful than I thought it was going to be.
1, If you haven’t already add contrib and non-free to your sources.list file, then update.
2, Run this aptitude -r install linux-headers-$(uname -r|sed ‘s,[^-]*-[^-]*-,,’) nvidia-kernel-dkms
3, Install nvidia-xconfig and run it to generate your nvidia xorg.conf
Your nvidia should now be working.