A few weeks ago I lost a chunk of personal photos to the digital abyss. These were mainly photos of my first child from 1mo to 6mo. I was able to recover 1600x1200 versions of many good ones because I had uploaded them to posterous albums. And I was able to recover videos from the same time period because I had given a DVD of them to my mom. But we did lose larger sizes and and a number of original shots.
I do a lot of backing up, but nevertheless there was a big hole in my system that I will relate in hope that you don't make the same mistake (and I don't make it again).
First, here's what (I *think*) happened. We store our photos in the desktop version of Picasa. Because we take a lot of rapid fire photos of kids, and most of those end up blurry, I had turned off the delete warning such that when you press delete it actually deletes the photo from disk.
This ended up being a bad idea, and I've turned the warning back on. Yes, it is a pain when deleting a lot of files, but it saves you from accidentally holding down the delete key and deleting six months of photos. Who would do such a thing? I believe one of my two kids did that at some point when I wasn't looking and didn't notice.
And that's the crux of the problem/hole -- I didn't notice there were a chunk of missing files. It could have been done 6mo ago or more. If I had known about it, I could have restored them from a backup, but because I didn't know for such a long time, regular backups kept on occurring, and the schedule expired the old ones that contained the missing files.
We currently use a couple of forms of backup. Locally, we store media files on a Windows Home Server with redundant storage (so a disk failure won't kill anything). Remotely, we use Jungle Disk, which backs up the changes in our media files nightly to our S3 account on Amazon. But as stated we have Jungle Disk only keep backups around for so long, so by the time I did notice the files were long gone.
My new solution is to add one more layer to this process: Amazon Cloud Drive. The distinction between it and Jungle Disk and something like Dropbox is that it isn't syncing. Instead, it is a snapshot of my files at the time I copied them. Since I know at the end of the year (my media is organized by year) that year is OK, I can now copy it to Amazon and know that it will persist there if I run into trouble with the other backups.
One wrinkle here is the interface to Amazon Cloud Drive is Web and you can't easily copy whole folders via their interface. So I installed (and eventually bought) Gladniet Cloud Desktop that lets you mount the drive like a normal drive and then drag and drop stuff to it. Super useful.