newegg.com offers the Western Digital Caviar GP 2TB Serial ATA 3Gb/s Internal Hard Drive, model no. WD20EARS, for $99.99. With free shipping, that's $0.05/GB. This "green" product promises reduced power consumption compared to other models by up to 50%. It features a 64MB cache.
Features
The Western Digital Caviar Green 2TB Hard Drive uses less power and supports quieter, cooler-running desktop PCs. Its breakthrough 64MB cache makes this hard drive suitable for high-performance home and business computing, as it can handle high-end data-intensive and multimedia applications.
This hard drive incorporates WD’s GreenPower technology, which yields lower operating temperatures and low acoustics, best for ultra-quiet PCs and external drives use. The IntelliPower delivers a fine-tuned balance of spin speed, transfer rate and caching algorithms; IntelliSeek Calculates optimum seek speeds. All the features help the drive to operate with lower power consumption and reduced noise.