WD Blue 4TB Hard Drive Review: A Decent Hard Drive That Won't Break the Bank
WD Red Plus 4TB NAS Hard Disk Drive - 5400 RPM, 3.5" - Newegg.com
Seagate ST4000NM0023 4TB 6G SAS LFF 3.5 7200 RPM hard drive
Amazon.com: WL 4TB 64MB Cache 5400RPM SATA III (6.0Gb/s) (Low Power & Heavy Duty) 3.5" Internal Hard Drive (PC, NAS & CCTV DVR) - w/ 1 Year Warranty : Electronics