A capacity of 500 GB should even be sufficient for data archiving purposes. Even if you only stored photos at five or six mega pixels (up to 2.5 MB per image) this big Barracuda will be able to host 200,000 of these. You could store over 80,000 high-quality MP3 files (it will take five minutes to save approximately 6 MB at 192 kb/s).
For enterprise environments, larger hard drives help to increase storage density. The more capacity you can fit into a full size 19" rack, the better, because space, energy and maintenance requirements are reduced.
High capacity RAID arrays require fewer hard drives in order to hit common capacity points, or the total storage capacity may be increased by using the same or larger number of drives. Reducing the number of hard drives is attractive for arrays that do not necessarily have to offer the best performance specs. Since fewer hard drives also implicate fewer components that eventually will fail at some point in the (hopefully distant) future, compact RAID arrays are more reliable.
Thus, everyone should not simply opt for the largest hard drive possible. As always, purchasing state-of-the-art products comes at a price premium. We recommend first thinking about the capacity you really need. That should be anything up to 250 GB for most average users, which is what those in the industry call the sweet spot today. Then go and find the hard drive that delivers the best bang for the buck - our regular reviews should be a good help, because we keep including benchmark results of products we already reviewed..