Nice set up. I also have a Zotac mini. It bought a bare bone unit from Newegg. However I use it as an HTPC. I run XBMC and Plex Media Center on it. A Raspberry Pi is a much lower cost option, but your are limited to USB 2.0 hubs.
Thanks! Yeah, I know this wasn't the most cost-efficient option, but it's a one time cost. And this way I can stay as generic as possible - running Windows 7 means I have a familiar environment, and it should be pretty straightforward to expand the rig.