After emerging the nvidia stuff as per docs on web-site, nvidia works fine and I have rebooted my machine several times after emerging nvidia with no probs. However, once I emerge another package and reboot, the nvidia drivers will fail to load. I cannot seem to find a log file for the error message (using metalog) or would have posted error messages if any were recorded (none are shown at boot up other than red [ !! ]. To fix problem, I re-emerge nvidia drivers and they again load without a problem at next reboot. Some packages I have emerged that broke nvidia: apmd (most recent), aterm, gentoolkit, gqview.
This shouldn't happen anymore (recent fixes). Make sure that /usr/src/linux points to the kernel source tree that the nvidia drivers should be compiled for.
