#1: Kids Protection Plan
If you've got kids, you have to have a Kids Protection Plan; most important thing, no matter how much money you have. Names guardians for short term, long term, and other docs to make sure that everyone would know exactly what to do if you were in an accident, including having an id card for your wallet.
#2: Living Trust
Living Trust; if you have assets over $100,000 or own real property with a gross value over $30,000 then, in California, it typically makes the most sense for you to have a living trust.
A will is the legal document that allows you to say where you want your "stuff" to go.
#4: Power of Attorney
If you are incapacitated, you'll need to name someone you trust to have the authority to make legal and financial decisions for you.
#5: Health Care Directive
In California an Advanced Health Care Directive gives someone ability to make health care decisions for you AND it makes sure that your wishes about what you want to happen with your healthcare are known.