Currently, the 7K400 is a scarce beast -- you can't hit your favorite web store or local shop and buy one. Hitachi spokesperson Beth Ellerman estimated $410 for the price, but availability will be limited in retail for some time to come. This makes sense, as the target for this drive is media storage and near-line backup.
Hitachi is offering a three-year warranty on the drive, however, so should you get your paws on one, you'll have warranty coverage equivalent to the other Deskstar 7K drives. However, the presence of 10 heads and five platters necessarily means more moving parts, which can affect long term reliability.
In the end, you should probably opt for something with lesser capacity for your desktop system. But if you're planning on building that home theater PC using ATI's spiffy new HD Wonder card, then this might just be the drive for you.
