I got my 360 last week, and it's been running at about 97%... It froze once during PGR3, which was no big deal, and the DVD drive is the loudest in ALL functions that I have ever heard...
Spinning is loud, seeking is loud, closing makes weird noises... all of this is pretty normal, but yesterday it started making a loud screeching sound every now and then... It sounded like a dodgy fan belt in the winter... Probably what cats sound like when they are dying. I checked the disc and there were no scratches. Weird. It only happened the one session though, so I'm going to give it some time and see what happens (I love extended warantees). I think it MAY have been caused by the system not being entirely level (it is now), but who knows.
Only other problem: a couple of times now, I've sat down and held down the guide button on my (wireless) controller, waited, and, waited, and.... system never comes on. The controller does, and the ring of light circles and circles looking for it's master, but nothing. And it isn't the controller, because when it happened once I tried it with a second controller, and still nothing. It HAD to be turned on manually (Amazing how spoiled I am... I've been turning consoles on mnaually for my entire life, but after a week of remote, I curse at having to get up and hit a button).
None of these are enough to try and get a replacement unit, but they are still kinda weird.. Anyone experience anything similar?
p.s. I'm using an Acoustic Research Optical cable... fits like a charm and has a nice satisfying click. As for the people with loose opticals.... I had to do this with my mom's cheapo receiver before, and it might work for the 360, but may end in disaster... The inside of some optical recepticles contains a slightly springy metal clip thing, which is what provides the force to keep it in there. I was able to fix a loose connection by going in there with a little piece of plastic and giving the metal clip thingy a slight bend, making a snugger fit. This can end badly of course, so do it at your own risk.