As above, preferably as cheap as possible 
It's mainly for streaming media from my PC to PS3 using PS3 Media Server. I would like to add some resilience to hard drive failure.
Been looking at things like the Drobo or the Edgestore DAS. Or maybe even just using the onboard RAID on my motherboard, if that will do the job just as well, but I would prefer some kind of hot swappable caddy for the drives.
Anyone have experience of the above and able to comment?
Thanks!

It's mainly for streaming media from my PC to PS3 using PS3 Media Server. I would like to add some resilience to hard drive failure.
Been looking at things like the Drobo or the Edgestore DAS. Or maybe even just using the onboard RAID on my motherboard, if that will do the job just as well, but I would prefer some kind of hot swappable caddy for the drives.
Anyone have experience of the above and able to comment?
Thanks!