Also, just because I am all about KISS, you can REALLY do an out-of-the-box home entertainment setup with a WDTV and one of these:
http://www.amazon.com/Personal-Cloud.../dp/B00AGI7I2O
They offer a 4, 6, and 8TB model...all do RAID1 (as far as I can tell). The 8TB model is only $625 which is actually a pretty screaming deal...the drives are user-serviceable too so if one of them takes a digger you can just swap it out yourself.
*edit* 8TB is in JBOD mode, the 8TB model would be 4TB in RAID1 (as far as I can tell).
Add in data your favorite torrent site or some ripped media from any laptop and you're golden.