Just a note on drives, I bought a 3.5" hybrid SSD drive from Seagate with 2TB storage some months ago and that really made my P3D installation fly. The adaptive memory technique stores often accessed data in a NAND / SSD cache on the drive, and I can confirm that this really works and brings loading and writing times to SSD speeds. The prices are only slightly higher than for standard desktop models.
When you buy one just watch out for the model, the drive is in it's third model iteration by now.
Cheers,
Mark