I have had the miserable experience of losing valuable information on both an SD card and an External Hard Drive. Now, I'm a little paranoid about my data.
When it comes to my WIP I worry as we all do about losing all of my hard work.
For the last several months I've been using an online venue called Drop Box. It enables me to sync my selected files across my three computers and always have the most recent changes on whichever computer I decide to work on.
I hadn't even thought about it until this morning when I responded to a thread about mobile computing using a laptop, but they offer 2 GB of free storage.
You can check them out by going here http://db.tt/OsQV0n3
I am very pleased with their service.