It depends on what kind of drive you're getting. If you want a 10000 RPM, definitely get the Western Digital Raptor. Otherwise, the Seagate Barracuda w/ NCQ is the best 7200 option for sheer speed and low noise.
WDs are really good for their raptors. Their 7200 drives are good also, but the Seagates are more quiet and faster. They also have NCQ which speeds up requests, a feature that the WD lacks.
or this, i jsuit put this here cause soemone said it was quite, but really i dont care about noice, cause anything quiter then the system i have right now, the PSU RUNS NON STOP AND ITS SO LOUD. ITS LIKE A HAIR DRYER MUFFLED THROUGHT THE CASE