Seems my closest bet is the failure to detect my AGP chipset:
This should be something like:
hw.nvidia.agp.status.driver: freebsd (agp.ko)
I know linux's agpgart had problems with my chipset as well. I had to use a module option to force it to detect it.
I'm gonna have a look at the FreeBSD agpgart implementation when I get around to it.
My library ouputs wont help you as I've replaced nvidias libraries with Mesa 5. I need OpenGL in order to work and I can't have a system that hangs every 5 minutes. But as I said, I had the correct libraries installed when I tried, I had no stale libraries from another package. And glxgears is linked against libGL.so.1 as the new standard specifies.