Nexus One: Common Screen Problem
If your Nexus One screen looks anything like this, HTC is aware of the problem. They said they are working "day & night" on a "fix."
It sounded like they weren't quite sure why some phones had problems and others did not.
At this point they're hoping for a software/frimware fix, but a recall is not out of the question.
So they basically told me to be patient and wait.