I can honestly say that I have purchased 10 LCDs for myself at various times and NEVER had a dead pixel out of the box nor has one ever developed. Most of the LCDs have been sold since then but I still have 5, 2 which are over 4 years old and still have no dead pixels. At work I have installed in the last year alone over 100 19-24" LCD and only ONE of them came with a dead pixel out of the box and the other 100+ have not developed any deap pixels at all and my users are abusers. I guess we have been extremely lucky!
*knocks on wood*