You will need the nvidia video drivers to get the GPU working. If you later switch to a normal AGP card you don't have to change anything. (both cards are nvidia ...)
For sound (kernel has support now too, but take nvidia's drivers) and lan you will need nvidia's nforce drivers.
You want to use your own modelines. (custom KHz, interlacing ..) All that is possible but not that easy. You'll need to look into XFree86 modeline programming.