Grrr... just tried what you suggested about removing that line, then just removing the BUSID line, then removing both and on each occasion computer says no i.e. hangs at the login screen.
I wouldn't be so fussed but I need the 3D acceleration to run Wine properly...
I just wonder if there's some command line command that will look at the card and the NVidia driver and say 'Ah yes, this is what you really need in xorg.conf and also these other files too!'.