Install latest nVidia GeForce drivers

The Dell Inspiron 9400 I have comes with the nVidia GeForce Go 7900 GS graphics card. There are "restricted" (closed source) drivers for this card with superior support for hardware graphics acceleration compared with the default open-source "nv" drivers.

To install the nvidia drivers I used "Method 1" from this excellent guide

1. installed the nvidia-glx and linux-restricted-modules-2.6.15-23-686 packages
2. enabled the driver using sudo nvidia-xconfig
   
3. added the nvidia-settings dialog to the Application > System menu
4. Restarted xserver (Ctrl-Alt-Backspace)
   

It worked flawlessly.