The recent flip flopping on Proposition 8 in California ("only marriage between a man and a woman is valid or recognized in California") really drives home the need for same sex couples to make a plan for what happens if a partner becomes mentally incapacitated or dies. Recently Jane Bennett Clark outlined what same sex couples as well as unwed heterosexual couples need to do in order to "avoid being caught in legal limbo" for chicagotribune.com:

1. Get financial and health care powers of attorney - Without these important legal documents in place, your blood relatives, not your partner, will take charge of you and your finances in the event you become mentally incapacitated.
2. Consider a cohabitation agreement - This is a prenuptial agreement without the nuptials.
3. Sign a last will and testament - Without this important legal document in place, your blood relatives, not your partner, will take over your estate after your death. (One thing that I disagree with Ms. Clark is taking this important task on yourself - in my experience do it yourself wills don't work for married couples or singles let alone same sex or unwed relationships).
4. Consider joint ownership but watch out for gift tax issues - Joint ownership with right of survivorship will avoid guardianship if a partner becomes mentally incapacitated and probate after a partner dies, but unlike married couples, unwed couples cannot take advantage of unlimited gifting.
5. Provide for the surviving partner - Life insurance is one way to leave cash to the survivor to pay bills and replace lost income. You should also make sure that the beneficiary designations for your 401(k)s and IRAs are up to date so that your partner is named as the primary beneficiary.

• Jane Bennett Clark - Securing the future as life partners
• Same Sex Marriage: Don't Forget About Your Estate Plan
• Unwed Couples: Don't Forget About Your Estate Plan
• Should You Write Your Own Will?
• Overview of the Essential Estate Planning Documents
• Understanding Joint Ownership of Property
• What Gifts Are Subject to the Gift Tax?