Well, you know how people complain about PC's being too loud? I left my '360 powered on and had gone somewhere for the evening. When I returned, as soon as I opened the door and stepped in, I heard the tell-tale hum/whine of a computer and thought, "damn, I left my computer on," when in fact it was my '360. They're not AS loud as a non-silenced computer (I yell 'Clear for takeoff!!!' when I turn on mine), but it's definitely louder than any other system that I've ever had, certainly louder than a PS2...