I'd also like to point out that I strongly advocate pre-built NAS solutions for media (and personal document) storage. They are for the most part easy to set up, serve files to all the devices in your location, are fault-tolerant, and the drives are easy to replace with minimal downtime in the event of a problem.
I see potential issues having media and/or other files stored on a PC type device running a standard OS. If the OS becomes corrupt, or you get a virus, access to that media may become a problem. You can go down the unRaid/FlexRAID route as others have suggested, but the overall cost in hardware for a scratch-build may outstrip the cost of a low-cost budget NAS in the long run, and you may be spending a lot of money for functionality you don't really need.
If you want an easy to configure, set-it-and-forget-it solution, have a look at the 2/4 bay solutions by all the common NAS manufacturers (Netgear, QNAP, Synology, Thecus, etc.) get the drives to fill it and be happy. The number of bays you require will ultimately be dictated by the overall quantity and type of file(s) you want to store on it. A lot of NAS devices also have pre-installed features to allow access from a remote location, or can be configured to do so via user add-ons, and the devices are also a lot more portable than a home-brew solution.
I Use 2x ReadyNAS x86 NAS units (An Ultra and a Pro). I have the content from one mirrored to the second one. The primary is used for configuration of the stored content, and remote serving / downloading / etc. and the second serves my various XBMC-enabled systems around the house. For me it works very well.
Good luck, regardless.
Joined: Oct 2011
Location: United Kingdom
2014-05-23 20:47 Post: #16