I too went through this process pretty much the same as what you have outlined here.
I too am stuck with no 3D support (ATI 9800Pro and same Nforce board)
I did try re-compiling my kernal but I got it wrong. However the new compile just showed up as a possible boot option in LILO - so it was easy to revert back.
If you try and get this to work, please let us know.