iPod Touch: 'Negative Black' Screen Issue
iLounge posts an extensive review of the iPod Touch and found that in comparison to the iPhone, it was somewhat disappointing. Of note, they felt that the video screen had a shallow viewing angle and an unusual "shimmering effect" in dark spots.
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.