i have a seagate barracuda 7200.11 500GB hard drive, and it's very quiet. hard drives actually have adjustable acoustics levels. my old dell computer had an option in the bios to adjust the hard drive acoustics mode to either silent, balanced, or performance, and the difference between the 3 is huge. on silent, it literally was silent. but you don't need to have this option in your bios for it to work. HDD inspector and im sure several other programs can adjust the acoustics mode from within windows.