You should take a look at the Bash Prompt HOW-TO at the Linux Documentation Project -- specifically the section on Colors.

For example, in order to change the color of the bash prompt to cyan for all users, look for the following line in /etc/profile (as root):

PS1="\u@\h:\w\\$ "

Change it to this (additions bolded):

PS1="\[\033[1;36m\]\u@\h:\w\\$\[\033[0m\] "

(Dunno about the NVidia part of your question. Nothing radically changed when I installed 'em...)

If you only want the changes to apply to your user, instead of all users, add the line to ~/.bashrc instead of /etc/profile.