Just to keep the mac peoples feet on the ground, I bought 2 27" imacs three weeks ago; both faulty out of the box. One would not wake up, and just discovered the second one won't partition the internal HDD. swapped out the first one, probably do the same with the second.
Just goes to show they are not the bomb proof pieces of perfection they claim.
That's unfortunate, but again - no one ever said they are perfect and never go wrong, but independent surveys confirm that they are generally one of the best, if not the best for reliability.