This is how I installed nVidia drivers on a fresh 9.04 Crunchbang install
First grab the drivers from here
put them in you /home/user folder and make the file executable!!
Right Click, Terminal
Install these three applications to prepare for the driver installation
sudo apt-get install nvidia-settings binutils gcc
press CTRL+ALT+F1 to take you into a non-X terminal thingy
authenticate with your user account
sudo killall gdm
sudo killall openbox
Run through the installation wizard.
Afterwards, reboot your GUI, enabling the drivers, by typing (thx alt-SysRq-boom!)
sudo /etc/init.d/gdm start
or just reboot..