Taking care of a WordPress operation is a two-pronged affair, inasmuch as the files are stored in two wholly separate locations: the Web server itself contains the WP core files and the design elements, while the actual posts are kept in a database elsewhere.
I download all the graphics and such to my home box before posting, so I already have copies of them in case of Dire Emergency. I hardly ever see the database, though, so a plugin copies it out on a regular basis, gzips the copy, and emails it to me.
Or anyway, it used to email it to me. The database is now so large that the gzipped copy is up to 20 megabytes, just at the point where the mail server balks: “Too big, pal.” For now, I’m fetching it via SFTP, but I’m thinking I ought to be considering other options.