I am not usually a plugger of software on this site, but I have found Dropbox so useful I just had to mention it.
If you use more than one computer for the same work, or you simply need a backup space for essential work, then Dropbox does the job. It keeps up to 2GB worth of files sync’ed with a Dropbox folder on your computer.
Since I use a desktop at home and an old laptop for when I am on the road, it means I dont have to worry about moving files around since it is take care of automatically.
An added bonus for me is that if you click the following referral link, I get an extra 250MB space for free: