If you're in a bigger company, the IT department may have some smaller PCs like this to get rid of. Mine gave a bunch out, I have a Dell optiplex - but instead of the thin client it's a small i3, with a 320gb hdd and 6gb ram. It's dead silent and runs all the home server things like a champ, oh - and it was free.

But I'd still own a number of raspberry pis since they're great for hacking or just to support a cool mission (in my opinion).