Running Microsoft's Server Essentials 2012 Workgroup edition, Seagate's Business Storage Windows Server NAS box is a good fit for Windows-centric houses. But it's pricey for the features provided.

If you're looking for a small server rather than a custom NAS device, you might like the Thecus W2810PRO that runs Windows Storage Server 2012 R2 Essentials, giving great power with a learning curve.

QNAP Expands Turbo NAS lineup with New Entry-level 4-drive Rack-mounted NAS Server for Workgroup and SMB Customers ...