Using nvidia's own installer will likely work first time every time. (You will have to restore the symlink on xorg updates if you do not change the directories). The first time I tried Debian's modules, it did not work. Later on, they did but with a lower frame rate. In any event, use m-a (module assistant) and compile against your kernel sources (or headers which need be installed) rather than look for any precompiled modules. This should work.