I just added a second Seagate ST3500630 Barracuda ES drive to my HP EX470. I purchased it online at Computer Geeks (www.geeks.com). It is the ST3500630NS drive and they have it on sale today at only $83.95. I installed one I received a few weeks ago and have had zero problems. Anyone who has purchased an EX470, this is an upgrade that really turns your system into a EX475.
The HP MediaSmart Server is a great box for anyone who has a home network. With the add-in Advanced Admin Console, I have changed my Workgroup Name, installed printers that were attached to a PC and Stream my music to a ROKU Media Player all with out keeping my PC's on 24/7.
Just the savings in utility bills and not having to purchase print servers and network drives, you can save a lot of money.