I have one of the HP docking stations for my laptop, which provides NAS (and includes a built in drive as well), and also a network printer facility.
It's used to keep data copies and drive images. Go for a good NAS device, image your PC system, keep duplicate copies of all data. The first time a drive goes down you'll realise just how well spent your money was
I don't use mirrored drives, but duplication software that makes a copy of every file plus a zipped up copy on a separate USB drive of every file deleted as well (they're auto deleted after 14 days) - it's rescued me many times.