So, I have been reading many posts where people say that they got the WD Scorpio Blue 500 GB, or another drive, for their unibody MacBook Pro and they notice it is much louder than their stock drive. They report a found kind of like a fan. Anyway, the sound goes away when you press in the right-hand corner of the MacBook Pro. Well, I had the exact same problem. I couldn't figure it out, what was pressing on the corner doing? Then I figure it out! It's sealing the battery compartment. The door for the battery on the MacBook Pro is actually pretty loose, when you press it closed tightly from underneath it does the same thing as pressing in the corner - the sound from the drive is reduced dramatically. My solution was to take some strips of clear tape and carefully put them around the battery door on the bottom. You cannot see them when the computer is open normally. At least for me, this has solved the noise issue. Hope it can help someone else!