Amazon.com: Western Digital 1 TB 3.5,Western Digital AV-GP WD40EURX 4TB 3.5-Inch 64 MB Buffer Internal Hard Drive,Amazon.com: Western Digital RE4 WD1003FBYX 1TB 7200RPM 64MB Cache SATA 3.0Gb/s 3.5in (Enterprise Grade) Internal Hard Drive - [Renewed] w/ 1 Year ,Western Digital Caviar 22100 WDAC22100-00H 2.1GB 5200RPM ATA IDE 3.5,Western Digital Caviar 22100 WDAC22100-00H 2.1GB 5200RPM ATA IDE 3.5