I bought a brand new 30 inch display and when it arrived I noticed within a day a single dead pixel in the centre of the screen. I phoned up apple and they told me it would need a minimum of 5 dead pixels to warrant a replacement.
After spending that much on a brand new top of the range screen, I was not having a dead pixel right in my line of vision so I got them to take it back and went to my local apple store and bought another.
Apart from that little incident, I have never had a problem with Apple screens, but I do think the 5 pixel or more policy stinks.
Barney