I joined Carbonite a few months ago and am now a big fan. It automatically backs up to "the cloud" any new or altered file once a day. So if I change something today and want to go back to the original file tomorrow, I can grab the older version from my Carbonite files. (Yes, I know Time Machine on the Mac does this as well, but I also like the added protection that if my laptop or desktop are stolen, my stuff is still recoverable.) Unlimited space. I believe it's $55/year, but you can easily find offers that give you two months free.