I use this build as my FreeNAS server on my network. This thing is more than adequate for what I'm trying to do, which is run a storage server with a few jails, like CrashPlan and Plex.
NOTE: The last image is a screen grab from FreeNAS's Reporting tab showing the CPU and load figures, since some of you were interested. Even though it's only an i3, it's a GOOD i3 -- and a bit overpowered for the box. I bought a Haswell with AES-NI on purpose because I am encrypting the pool of data that will live here.