In response to a post asking about why I went with an external USB storage device, I've decided to respond as a new post.

The device I bought lets you take any regular internal hard drive and mount it as a USB drive, then remove it whenever.  The advantage is that you can store gobs of data and have easy access to it from any computer.  Just like a USB key on steroids.  With USB 2.0 you should have speeds close to internal, though as it turns out I have a driver issue limiting my speed right now (ARGH).

As for why I bought this as opposed to buying the external USB disk, it's no different.  Just buying it piecemeal instead of pre-assembled.  It's cheaper this way.  Plus I can get any size drive, and even plug in a CD/DVD drive if I wanted to.  In fact, since then I bought a 2.5" to 3.5" adapter so I can plug in a laptop drive through the interface as well.  Very nice!

He also asked about how it compares to NAS (Network Attached Storage).  I'd actually like to get a unit for that as well.  I have a computer sitting in my "LAN closet" (under my steps) right now.  This has 200 or so GB full of video, pictures, and music.  The unit also doubles as my media center computer (note the lower case -- it's actually running MediaPortal), but otherwise I wouldn't want the expense of an additional full-blown computer just to mount some hard drives.  I like the idea of just plugging a device into the network to increase my home storage space.  Nice for backups and common media.

As for speed, a USB 2.0 device is 480MBps, compared to 10 or 100Mbps on any network device (unless you go gigabit Ethernet).  Speed is better locally, plus you gain the portability of all of your data.  I keep all of my My Documents and other important files externally now.  If the PC crashes I lose installed apps and settings (though I will be backing them up to the external drive soon), but all documents are safe.  I can pop it into another computer at home or at a public library and have full access to all my stuff.