The CalDigit S2VR RAID enclosure
If you've ever spent time editing video, you probably know how frustrating it can be to wait helplessly for your computer to catch up with the edits you're making in whatever video editing application you've chosen. Editing streams of video in real time eats up a great deal of storage bandwidth, probably as much as your system will allow. Of course, there are other applications that also hunger for a lot of data transfer, but video editing is probably the most compelling reason to consider striping a couple drives in RAID mode to get some extra speed out of them.
If you're going to set up a RAID array anyway, there are a few reasons to consider an external RAID enclosure; the most obvious is that your hard drive slots may already be full, perhaps with IDE drives. Another good reason is that there's only so much physical space in a PC case, and yours might be getting pretty cramped. Perhaps you're just simply uncomfortable with having to navigate through that jungle of cables in your PC case. Finally, you might just value the idea of having a mobile storage solution for your work.
Regardless of your incentive, external RAID enclosures can be a really good idea. Let's take a look at one from CalDigit.