Macbook
I use my macbook for personal, school and some work stuff, I consider it my most important machine, and it contains a lot of important files to me, including all the archive of projects I’ve done in the past1. I rely on Time Machine to do daily backups of my hard drive (and that can be restored in a couple of hours). I also do weekly/monthly backups to my Desktop and my Network Drive.
VPS
I own a VPS that runs all of my websites. It has a cron script every day that backups to disk the mysql databases, and it backups the important folders every week. Then I rsync it to my macbook and it’s replicated the same way.
I rely on Google to save my email. All my email accounts go to my gmail account, even my alcidesfonseca.com email. So there is always a copy on the original server, and another in Gmail.
Cloud “stuff”
Twitter, Delicious, Flickr, Google Reader OPML, Contacts, etc… I like to have a backup copy in my hard drive every month. I have some scripts for some, for others I just go to the website and download it. If your delicious account is as important for you as it is for me, you should also download it.
1 I’ve lost my archives from the pre-2005 years, and I know the pain it has given me. Your past projects are really important for you as a programmer.