Have assembled a quiet pc using Cooler Master sound proofed case an expensive high efficiency power supply, an ASUS fanless graphics card and an OCZ SSD for the C drive. Very pleased with the result except when this drive is running it vibrates the whole machine and the desk - just a little but enough to annoy.
I brought two of these drives for my new pc and both are fitted to removable bays and both vibrate in the same way so I assume it is a consequence of them running at 7200rpm speed? Otherwise they are very quiet in operation - no clicking sound during read/write operations.
This new pc stops the drive if not used for a while to save or open work, and it's noticeable when it stops spinning, and when it starts up again!