I'm planning on re-entering the Mac world early next year. I'm either going to go for a high end iMac (24") or a low end mac pro. The main decider will be the price and my available cash. One issue that concerns me is noise. In short, how loud are the various machines? My current PC sits there making a noise like a small turbine and I really want something as near-silent as possible as a replacement. Thanks for any help.