I was one of the unfortunate ones to get an iPod touch with a wonky screen. I waited a couple of weeks to see what was up, and once Walt Mossberg said the defective screens were only an early production problem, I was off to the Apple Store to exchange mine. While we still don't know if the problem has been resolved completely, I can say that my iPod touch has a screen that looks as great as advertised.
I made an appointment with the Genius Bar guys who did some video tests of their own, and came to the same conclusion I did. No questions asked, they took my old iPod touch, handed me a new one, and I was on my way. Pretty painless overall.