I've got a 27" i7 here that is finally flawless, with one exception. The stand seems to be a little loose. I study alot at my desk and whenever I use my eraser, it shakes my desk just enough to cause my mac screen to slide down to the bottom position. I know that this isn't normal, and that its not my desk because I returned four of the imacs before the refresh for various problems, and this never happened on any of them. I really don't want to return this thing because its in very good shape, but another member posted today that he had the same problem with a loose stand, took it into the apple store, and they replaced it rather than tighten it up. That makes me think that tightening this thing might not be as simple as I'd hoped. Anyone know anything about this? Thanks.