Hard drives...

SSD is the future according to my IT degree that Im doing. It is faster and you can be more rough with it as it will withstand movement and shock
 
If you don't go for a SSD then in my experience the Samsung Spinpoint is much quieter than the WD Caviar Black. I have a 1 TB in both.
The Samsung is suppose to have an acoustically designed casing to reduce Hdd noise.
 
For me, hard drives are obsolete now.
The SSD is faster and it has a long enough life time so it wins.
My next machine will have 3 solid state drives as follows :

1. Operating System and applications.
2. Sample libraries.
3. Cubase projects.