Western Digital WD Blue WD10EZEX 1TB Internal Hard Drive for $44.99 shipped.  Here is a screenshot for reference. Alternatively, it is available at Best Buy for $44.99 shipped. It features 7200 RPM, 64MB cache, and uses SATA 6.0Gb/s interface.  Note that it comes in OEM packaging, which means no pretty retail box but is otherwise identical.