I like the idea of having my important files being backed up. Who doesn't. But where to back it up? Backing up to another disk does do the trick. But what if the hardware starts to fail. You can probably think of even more worst case scenarios.
I think, the most safe way is to backup your files to an external storage, outside of my house. Maybe an online backup. Dropbox is nice to use and it works quite good. But what if you have about 20gb of photo's taken by a high end photo camera? Dropbox's limit of storage is about a gigabyte... I must admit, For my documents it's quite enough.
At this moment, I think that Microsoft's Skydrive can do the trick. With it's 25gb storagespace, it will be enough at this moment for the photo's.
But actually, it is not that easy to perform automatic backups. It took me a while to figure out how.
What i did was the following:

1.
Copy all of your pictures to another location and change the file extention to .doc
Why you might ask. Skydrive is for some reason not allowing you to backup .jpg files. While copying the .jpg files it gave me a lot of api errors.
Incremental copy of the files (in my case, my .jpg photo's) to another directory can be done with xcopy:
command: xcopy \*.* \*.doc /S /M /H /I /Y

2.
Your Skydrive can be accessed directly with an https url. The exact URL can be figured by numerous ways. One way I used was the following: http://www.addictivetips.com/windows-tips/save-word-document-to-skydrive-office-2010/
Be ware that you choose map which is not publically accessable by anyone. So take care that you save your documents/pictures, only accessible by only you. But the trick here is, that you can see the url where your documents are stored in Skydrive. Before you are actually saving the document you can right click on an already existing document in your skydrive and choose properties. Then you'll see the url where the document is being stored.
Another way of finding the url can be done by following the url:
http://www.nirmaltv.com/2010/02/02/how-to-map-skydrive-as-network-drive-in-windows/

3. Download AllwaySync. http://allwaysync.com. You can the sync the map with the .doc files from step 1 with the https url, figured out in step 1.

4.  Finally you can automate the backup process. I've created the following batch script


@echo off

cls

rem Backup Pictures to SkyDrive

rem Copy pictures to doc files, incremental
xcopy W:\Pictures\*.* X:\Backup\Pictures\*.doc /S /M /H /I /Y

rem Sync pictures to SkyDrive
"C:\Program Files\Allway Sync\Bin\syncappw.exe" -e -m -l -s "4F0C1497E9A5A062AD06B978802E02AB"
The last line actually performs the Sync to Skydrive. The "4F0C1497E9A5A062AD06B978802E02AB" is the ID of the Sync Profile I created.
The ID can be seen when you create schedule in AllwaySync (View,Options, click on profile, Automatic Synchronisation, Use Windows Task Scheduler"