Personally, I would rather have the highest quality boot drive and
two additional drives, one for my primary boot and maintenance drive, the 2nd for dedicated audio applications and the 3rd for storage.
I'm still not comfortable with having all my eggs in one basket on some huge storage drive.
The new perpendicular drives like the WD and Samsung seem to be the way to go.
The speed and the cache size are the most important performance factors, in general, but for audio, you also want quiet operation, so Raptors are probably not a good idea.
Looks like the Samsung Spinpoint 1000GB is the leader of the pack with the 32 Mb cache, but again I worry about that much data on one drive.
More worthwhile reading http://www23.tomshardware.com/storag...=1016&chart=33
NewEgg is selling the WD6400AAKS for $119.99 if you use Promo Code EMCAEABBC.
A pair of these would be an affordable way to go.
I've been happy with my Seagate Barricuda, but so much has changed now with the new perpendicular drives.