The Western Digital Scorpio Blue consumes 30% less power than previous generation drive in the line, boasting "best-in-class power and performance." It features several technologies, including WhisperDrive, ShockGuard, and IntelliSeek. As you can probably deduce by their names, WhisperDrive reduces noise, ShockGuard boosts shock tolerance, and IntelliSeek calculates optimum seek speeds.
According to Western Digital's press release, the 640GB Scorpio Blue is shipping now via select distributors and resellers. Its current asking price is $149, and it ships with a three-year limited warranty.