Look, their needs are not mission critical. They can handle having their power supply out for a couple hours until they put a new one in.
There's no need for high performance hard drive schemes, either.
A decent form of backup, preferably an image with incremental image capability (Acronis Drive Image or a similar one that is available free) will be fine.
Their needs aren't mission critical as long as they're not in thin-client. That's one reason I didn't recommend that. We'll have to agree to disagree on what you call "high-performance hard drive schemes," though. Mirroring isn't actually any such thing - even with RAID1 you take a bit of a performance hit. It's for redundancy, not performance, and yes, I do mirror my drives at home, and yes, it has saved me.
As for backup, I'm glad you like Acronis and I may give it a try based on that recommendation. What it backs up to is another issue. I'm through with tape - it's expensive and it hasn't kept up with the drives it's supposed to be backing up. Optical media don't have the capacity. I'm in the position of returning to the USB hard drives I used to disdain. Live and learn...