Wow, that took me back a few years (subject of the links above that is). The design studio I worked for had the same issues.
The 1st lines appeared on the first machine 6 months after we bought it. Machine get's sent for repairs. Same week, the lines appear on the 2nd machine. We get told that this is not covered by warranty as the Apple cannot control the variables that contribute to this happening. (said it may be problems with our power in the building). After fighting with the supplier, they eventually replaced both machines with new machines. 3 months later, the same thing happens simultaneously to both replacement machines. Apple refuse to take any more responsibility, claiming that they have already gone beyond the call of duty the first time, still blaming it on dodgy power in our building. We make it clear that since the machines operate off dedicated UPS's which are barriers between the mains supply and the machines in case of power spikes or anything of that nature. In fact, all the other PC's were running fine without UPS's. Apple SA (Rotten Core Group) refused to acknowledge any fault from their side and quoted us on replacing the LCD panels. Can't remember the amount, I just know my boss's jaw hit the floor when he saw the cost involved. I remember saying 'That's impossible!' (so it must have been quite out-of-this-world)
We ended up researching on the Internet and found that there were many i-mac users with the same problem. The most curious thing, however, was that Apple were deleting any thread on their support web site that related to this problem. We started a support thread and within a few hours, we found many other users complaining of the same thing. A few more hours later, thread was deleted. We kept records of the deleted threads and used that as part of our appeal to Apple in the USA. After being pushed from pillar to post, we eventually found someone who contacted the Core group and instructed them to honour the issue as a warranty claim.
Core begrudgingly authorised the repairs at no charge. A couple of months later... the lines appeared again on one of the repaired machines and on the third machine we bought along with the previous two. The last I knew before leaving the company was that the decision made was to buy dedicated LCD monitors to use on the machines as all three machines were now out of warranty as far as Apple were concerned.
We later found out from an SA Apple technician, who runs his own Mac repair shop, that all of the machines released to manufacturers from the mid 2007 range were recalled from suppliers to get LCD 'upgrades'. Turns out the LCD screens from that range had an inherent fault, causing pixels to die prematurely or something on those lines (no pun intended). What really got to us though was Apple's insistence that the fault was not theirs, claiming it to be 'unique' issue that they were unaware of < This, after deleting any trace of evidence to prove otherwise from their own support forum...
Good luck with your issue though. I still love Apple products - but have no faith in the Core group and am very wary of Apple as a whole. Sure they need to keep a certain decorum, but not at the expense of those who buy their products.
Rant over! Continue, as you were...
none of these apply to me 
