They are a bargain but I need far more space. Ive already filled my Drobo FS which has 5 x 2Tb drives in it.
You just stack another one on top..
For £130 (with cashback), they are phenominally good for file servers.. a full 5 drives with WS2008 on idle is under 30W too.. Assuming the cashback deals are still on, it's hardly anymore then the 5 ICY Dock enclosures, and thats for a full server..
But I sense you would just rather build your own..
My advice, get some decent Hardware RAID cards if you want to have good performing and flexible RAID 5 or similar, all the software solutions are quite limiting, especially if you want to use the server to run other services..
I went from a 12 bay server using lots of eSata to expand to 20 bays to the microservers, and it's been much less hassle.. I have 2 stacked at the moment, I'll get a third when 10 bays runs out..
Of course, everyone's needs are different.. the issue I had was that getting any performance out of 12-20 drives was a nightmare, if you use the usual software RAID style SATA cards, they underperform and aren't very flexible for expansion in most cases.. or I ended up trying UnRaid and other alternatives (FreeNAS etc), all where a pain to get going and things like FreeNAS had many issues, with upgrades often requiring full RAID set rebuiliding as they changed the file system to newer incompatible versions.. Not to mention if I wanted some simple download abilities, installing was just problematic to the point of hardly being able to do anything more then basic file serving...