Do you have important data to store?
The question is a rhetoric one. If you haven't yet backed up your important data, you should think well over this saying: There are two kinds of people. Those who haven't yet lost important data, and those who make backups often.
Oh well, I can tell a bit more about myself. I am a writer and a system administrator, so I combine the paranoia of both. I write my works either in LyX or in Geany. I use subversion to keep all the versions of both my source code and fiction works. Oh yes, I also use Truecrypt and GNU Privacy Guard to make sure no one can read my most private data easily.
Fine. So far my paranoia is satisfied. However, the final question: where to store the backups reliably? Many years of thinking led me to the below answer: