I operate low budget so my way may not be suitable for you.
I always try to have a spare computer ready for emergency.
they are cheap enough that its not that big of a deal.
get a used server from
www.evertek.com I'm using an HP DL380 rack server right now I think it cost about $ 350 bucks.
I filled it with good 72 gig drives and now have more capacity than ever.
bought a 2nd one for a spare.
It has raid 5 with 1 hot spare so a hard disk issue shouldn't be an issue.
I also run mozy pro every night as well as an offsite to a home computer.
Hardware raid 5 or 6 is a good way to protect against HD issues