One of the things I did to help my productivity was to buy a netbook (running Windows XP Pro). Then I used Dropbox to host my files in a shared folder that I can access using either my desktop or the netbook. Now whenever I write on one computer I can be assured that as soon as my files are synched (and Dropbox does an excellent job making sure it happens without me worrying about it) I can switch to my other computer and continue writing. Easy Peasy!
I'm also now backing my files up in 4 places, specifically both my computers, on a separate hard drive specifically used for backing up my desktop, and of course on Dropbox.
I'm using the free version, which for my needs is more than sufficient. I could see if I was using it to share photos with others how I would need to upgrade, but txt files don't take up much space. I think I'm currently using about 1/100th of my available space.