The "package conflict" is because Debian installs various libraries using DEB packaging and the dpkg-alternatives system, symlinking driver-specific OpenGL shared objects so they get picked up at run time. The nVidia installer does not use packaging and simply clobbers the links with real libraries
Yep, I know. Had to delete a few soft links here and there (pretty much the standard approach to installing newer GCC versions too) Re installing the Debian packages should remake all the links if you want to go back. Dunno why is a big issue.
Anyway, whatever suits your boat. Its fun to me to install new drivers and see what's new. Somebody may want to wait until everything just works, its fine by me.