I jumped the gun too. The only problem that I've noticed so far is that Ubuntu didn't update my menu.lst properly.
How I realized this a bit peculiar. I couldn't get to GDM. So I edited xorg.conf to use the nn driver insetad of the nvidia. Once in X, I looked to see what kernel headers were installed, the right ones were. So there seemed to be no reason for the nvidia driver to not work. That is untill I looked at the uname -a. It was still booting the "old" kernel, so I had to edit my menu.list