OK, as of today the latest NVIDIA drivers are 177 in the repos. This causes a bug with the new Intrepid Kernel causing the window title bars on some systems to draw incorrectly. It tends to be an intermittent problem. This is a temporary fix using the NVIDIA 180.08 beta drivers.
Download the file you need for your architecture. It's NVIDIA-Linux-x86-180.08-pkg1.run for x86.
Close all applications and save everything.
Log in. Then run "sudo /etc/init.d/gdm stop" to kill you XWindows session.
Go into the directory where you put the driver and run
"sudo sh NVIDIA-Linux-x86-180.08-pkg1.run" or the relevant command if you downloaded the 64-bit version.
It will try to download a module, then ultimately recompile a new one.
When you log back into XWindows, the new driver should be active and the window drawing problem gone.
Hopefully NVIDIA will release a finished driver that will find its way into the repos soon.
If you want to go back to you old driver, you can do it using System / Administration / Hardware Drivers. It will still display the old one active in there, just swap to a different one, activate it, then swap back.