Newegg has the Western Digital Caviar Green WD6400AACS 640GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive for $65 with free shipping. Use coupon code EMCMLMP23 to knock it dow to $55.
Features:
- Reduced power consumption - WD has reduced power consumption by up to 40 percent compared to standard desktop drives with the combination of WD's IntelliSeek, NoTouch, and IntelliPower technologies
- IntelliPower - A fine-tuned balance of spin speed, transfer rate and caching algorithms designed to deliver both significant power savings and solid performance.
- IntelliSeek - Calculates optimum seek speeds to lower power consumption, noise, and vibration.
- Perpendicular Magnetic Recording (PMR) - Employs PMR technology to achieve even greater areal density.
- Low power spin-up - WD Caviar Green drives consume less current during startup allowing lower peak loads.
- Advanced power technology - Electronic components deliver best-in-class low power consumption for reduced power requirements and increased reliability.
Newegg.com - Western Digital Caviar Green WD6400AACS 640GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive (bare drive) -Bare Drive
Western Digital Caviar Green WD6400AACS 640GB 7200 RPM SATA Hard Drive $55 + FS 
