Title says it all. I got my first iMac over the weekend and I think it's great, fast, beautiful, compact and QUIET!!! My old tower pc sounded like a plane because it needed so much cooling for the Prescott P4 processor. But, how do you know if the iMac is on? Once the monitor turns off, there are no power or HDD lights on the front; and, as mentioned above, it's so quiet you can't really hear it running. Obviously, I can wiggle the mouse and see if the monitor comes on.