I know I've heard this quite a bit, and I'm sure you have as well - back your files up (and especially your photos). Years ago my method of back up included copying photos to CD and then to DVD. That worked well for awhile, until my backups required multiple DVD's.
Now, my system for backing photos (and files) up is to download them from the camera onto an external hard drive. Then, I make a copy of those on another external drive. This worked well until I started filling up the external drives. I also found that it was a bit of a pain to copy the photos to my wife's PC in the other room. So, in an attempt to make the photos easier to access, and to increase storage capacity, I added a 2-TB network drive!
After copying all of my photos from the external drives to the network drive, I realized that some photos were missing. This really started to bother me, and as I thought more about it, I could actually visualize some of those images, and the settings and people involved. With all of these thoughts floating around in my head, I began a quest to look through all of my CD and DVD's backups for the past 7 years and find those wayward photos. It took awhile, but I ended up finding them. What a relief!
So, now I have my photos on CD, DVD, external hard drives, on several websites, and now on a network drive. Luckily I haven't had anything catastrophic like a hard drive meltdown happen and really wipe out my photos, but I took this as a warning - back up your photos before its too late!
I'll leave you with an image that I enjoyed making, and was very relived to find the original: