Western Digital announced new high-end hardware today, introducing a 750GB and 1TB hard drive to their “Raid Edition” lineup. The SATA drives are both in the 3rd generation of the RE family, which Western Digital aims at enterprises. These drives aren't much different from their standard SATA drives, but are certified to have a higher MTBF, being constructed to last longer underneath the stressful environments that a server drive might be in.
Despite being in their RE line, the drives are not astronomically priced, at $199 and $249 for the 750GB and 1TB units respectively. You can read more about the new drives here.