Hitachi 4TB for $153
The Hitachi 4TB Deskstar 5K4000 'Coolspin' Hard Drive is only $153 after instant rebate at B&H Photo.
See review of the Hitachi 4TB Deskstar 5K4000 'Coolspin' at MacPerformanceGuide.com.
The 5K5000 is not the highest performer (the 7200rpm 7K4000 is notably faster), but for lots of storage and/or backups and/or lower power consumption, it’s a very good price.