How many dead pixels are too many dead pixels?

Ed Foster is on a mission to end dead pixels, or at least to figure out what company's policies are in regards to them. His latest post concerns Apple and where they stand on the dead pixel issue. Specifically, how many dead pixels do you need to have on your screen before Apple will replace it. Turns out there is no hard and fast number, rather a 'bring it to an authorized Apple service provider and let them look at it (though you might be charged for that)' attitude which is detailed in this KB article.

So dear readers, have you had to deal with a crop of dead pixels on some Apple gear? Did Apple replace it? Let us know in the comments.