I email most things to myself across two different email accounts. This is in part so that if I want to work on something I can do it at home or at work. This is only personal data however. Work data doesn't have easy places to back up and I can't and wouldn't email it home anyway.
If people are concerned with stealing my word docs of drafted statements of purpose, unfinished poems, excel documents regarding MFA programs, and etc, then let them. I would probably get more publicity from pursuing copyright infringement actions if they made unauthorized publications of my poetry than otherwise. I mean please. Go to. Hack me for my writing. Writing, and the internet, are literally the only things I use my personal computer for. Do I consider it important data? Yes. Would anyone else on the face of the planet? Doubtful.
I can't dropbox at work. :-/ And since I do the email back-and-forth in large part to have access to things at work, it kind of negates the purpose. I mean, I could also back up on dropbox. It just wouldn't mitigate the self-emailing in any significant way.