Not quite sure yet. I am a database admin/application developer by trade, and trying to see how I can leverage these for some projects I am working on crunching data. Also, they're inexpensive for what they are, so I know they will come in handy down the road. I bought 3 Dell MD1000's on the cheap, so I have the storage aspect of this project covered. It's all for a proof of concept right now, so I am on the hook for everything.
I am probably going to gut one or two out to make a larger machine that doesn't depend on these screaming fans, and recoup a few bucks by selling off the stuff I don't need from them (backplanes, cables, etc, etc).
I bought the Supermicro fans recommended in the other thread about making these thing quite, but have not had a chance to do anything with them yet. My father is a hardware engineer and I go to him with this kind of stuff.