Couple of days back my TeraByte HDD crashed and I lost almost everything, including my homedir. I will tell you my experiences and how my measures helped me lose not much data. So I will begin with one of the most important aspects. My BROWSER.
I have all my passwords stored in the browser and I rely on them so it is not stored anywhere else. Also, I have lot of bookmarks which help me do lot of stuff. Meaning, all these are very important for me. So, I had a backup plan for my passwords and bookmarks.
<a href="Xmarks (formerly Foxmarks)" target="_blank">Xmarks (formerly Foxmarks)
It allows you to save your bookmarks on their site or on your own URL.
If you have your own domain and you have a hosting provider, like I do, then you can configure Xmarks to save the bookmarks and the passwords on your domain. So, I downloaded this addon as soon as I could get my hands on a working system and installed this extension, configured Xmarks and was back will all passwords and bookmarks. Great to be up and running so fast.
BTW, I am yet to get a replacement for my HDD, working on Live Distro till then.