Apparently, a number of new iPod Touches have shipped with dim, defective screens. Apple has admitted to this and is handling the problem.
Apple claims that the issue was only with a "small number of units" and that it is "being remedied." Whether this means completely replacing the units is unsure.
Some users are even reporting that their new iPhones have similar problems, but it seems to be limited to iPhones purchased after the price drop.