That's basically my current setup, however since I rather have a "good" HD (currently a WD Red) as an added layer than only a run-of-the-mill USB drive (which f

That's basically my current setup, however since I rather have a "good" HD (currently a WD Red) as an added layer than only a run-of-the-mill USB drive (which for several reasons I've come to believe aren't as reliable), I setup a cheap Celeron-based computer for this. I still use my USB drive, but it's used much more frequently so I fear it might break some day. That's why I opted for the NAS-rated HD as a second layer backup. As a last resort I also use tarsnap for my very critical files though, so yeah, USB drives are good but I wanted a bit more peace of mind on top :)