My tip on using multiple drives is:
SSD 500GB for OS/Progs drive
2TB or larger (pending how much you do) 3.5" NAS 7200rpm Drive (RECORDING TO) all recording projects
2 TB or Larger 3.5" NAS 7200rpm Drive(pending how much Virtual Instruments you use, Drum Software, samplers, Kontakt Libraries,etc.) - STREAMING DRIVE
I have a SATA drive cage in the tower, for doing Drive Backups - and store clones in a safe.