As you may have too much data to go on even a few disks, you may find it useful to buy yourself an external hard drive which can be used as a backup for your whole data block, photographs etc.
It plugs into a USB port like other peripherals eg MP3 player, and you copy onto it as normal. If you have a lot of data, it would take a while, but you could copy it across in smaller blocks as required. When you want to update the back-up, you can copy across a later version and then delete the earlier one.
They come in all sizes and memory, some similar to an MP3 player.
We've just bought one for �74.99 which has 360 GB (very good value) from our local computer shop . The one I have is not very large, about A5 sizeish (5" x 8" x 1" deep)and is portable and easy to store. I also bought one for my daughter as she wanted to back up all her data for security.
Hope this helps.