I'll be the first to admit, it's the last thing on my mind. When you are busy working or even having fun, backing up can sem to be the last thing on your schedule.
So perhaps in one way or another, backing up can certianly make many repair jobs easier.
Here is a link to a PDF file you can pass on to friends and co-workers to hopefully make them aware that backing up data is important.
http://www.fragileavatar.com/Smart-Backups.pdf
And, if you do lose your hard drive, they make great drink coasters and those magnets are awesome for keeping tools magnetized and handy in a workshop. 
I got all my data backed up in about 7 different places. All of them holding the same data. I got a RAID 5 on a Server. I have also got several optical media backups.
So I figure, I am good
Although... It doesn't mean I still don't make boneheaded mistakes. Like having Vista erase my RAID set...
Luckily, i got the data back...
It's important to not only back-up your important data, but to have at least one copy of the back-up off-site, in case of a catastrophic event like a fire, flood, or earthquake. Keeping a copy of the latest back-up at a close relatives home, like your mom, is a fine example. Another would be in a bank safety deposit box.
Mutant_Pie
One thing I have learned about backing-up data, other than being more diligent about doing it.
Is CD and DVD media is nowhere near permanent. Use an external hard drive, or better yet data tapes if you really want to keep the data for an extended period. I've had burned media go wonky in as little as two years. So don't count on those CD/DVD's you burned to have what you want in the future.
Someone wise once told me:
Is there really anything on your computer that you really need to keep for an extended period ? Anything that you cannot live without ? For the most part no. After 6 months or a year it is usually not needed and if it is, find another way to store it.
DVD-RAM is rated for 30 years +. That is as long as you have a machine that can write to them. The latest LG GSA-H42N drive can write DVD-RAM media.
Plus being DVD-RAM, you can write to them frequently, as much as once per day since they were designed for backups.
I used to do it then slacked off. Just lost all my music (1100 songs) by accidentally formatting my drive while trying to do ubuntu.
The media is rated for that long ? I always thought it was the media itself that deteriorates over time.
I have a Sony firewire dual-layer burner that writes DVD-RAM but never played with it. Maybe I should use the DVD-RAM burning option.
I back up everything onto my media server since it has a 2TB RAID5 (real hardware controller)