While we are on the subject...
Western Digital released a "Caviar Black" edition of the 640GB drive.
The model is WD6401. It has the 32MB cache versus 16MB, dual processors (whatever that means) and 5 year warranty instead of 3.
DirectCanada currently has the lowest price for it - $90.
640GB CAVIAR SATA 7200RPM 3.5IN BLACK - DirectCanada
I have not been able to find any reviews or benchmarks of this HD. I wonder how the "Black" treatment improves over the already excellent WD6400 design...