iPod Touch: 'Negative Black' Screen Issue
Similar reports and examples have been posted on various message boards (Apple thread, MacRumors thread, Flickr set, Youtube Video), and discussion has been filling our iPod Touch forum.
The Washington Post's first look at the iPod touch describes the issue in more detail:
Unfortunately the 16GB unit I picked up at the San Francisco Apple store has a display problem that makes many dark scenes almost unwatchable. Video looks reversed out in dark areas, creating a very distracting negative effect.
The issue does not appear to affect every iPod touch, as at least one user has posted photos of an unaffected iPod touch.