I had problems with my PC LCD Monitor and sent it back, but the replacement they sent had 'dead' pixels (3 to be exact), as stated before the industry standard is 5. Luckily I had looked it up and when the guy asked how many I just said 7, that is when he told me that 5 were acceptable.
It also depends where they are on the screen aswell, aslong as there is not more than 1 in the center of the viewing area.
Pete.