How to Back-up Your Life from Stepcase Lifehack, that points out the critical parts of your life that you need to back up. I've written about this before in various forms, but the link below will take you to an easy-to-use backup script for backing up computer files.
Back Up Data from the Computer Monkeys
Of course, there's more to the article than backing up computer files. You also have to plan for contingencies in your personal life (plan on divorce, losing a spouse), money (of course! Wills, trusts, and insurance), and personal documents (like tax returns, birth certificates, and the like).
A home inventory is a good idea too.