On the NAS / WHS solution, i would recommend going the WHS route but agree with Chris on the build. HP box is a dumb solution. I built my own PC and installed the WHS OS on it. I got various add-ons running on it along with squeeze center and playon and torrent.

It does all my backup along with duplicating (something like Raid) and also allows me to access all my content on the web.

--Avi

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Samsung 65" 8500, xbox 360
Sunfire AV7702
Marantz AV7704
Sony UBP-X1000ES
M80s, VP180, QS8s, EP350