... Or The Staid WD1500AD
There is a strong argument against the Raptor-X: Why do you need a clear cover, if you are not going to be able to look at it after installing the drive? If it's the performance of this new drive you want and not the fancy cover, you may go for the regular WD1500AD Raptor (without the X) and even save $50. The WD1500AD follows the WD360 at 36 GB and the WD740 at 74 GB.
It is no coincidence that the technical data of the WD1500AD Raptor and the Raptor-X resemble each other. As a matter of fact, the top cover part is the only real difference between both models, giving WD quite a bit of flexibility in producing either to meet demand. Such a strategy is widely used in aircraft construction as well, where it is necessary to switch quickly and easily from windowless cargo models to window-equipped passenger jets.