Not too long ago, I filled out some paperwork that gives my parents the right to make "less-than-terminal" medical decisions for me in the event that I cannot make them myself. That way doctors can't just administer all kinds of useless crap and charge you for it later. Also, it means that somebody has my back when I can't come to the plate myself.
The health care surrogate is not to be confused with your living will. The living will is your decision on when you want them to pull the plug on life support. I think it is important to have a living will, not only for yourself, but even more for those around you. For instance, my mom's mom died of cancer. She spent her last days hooked up to a breathing machine. I don't remember exactly what here time frame was, but I think that she didn't want to stay on life support longer than 2 weeks. When the time came and my mom had to end her mother's life, she was just following her mom's wishes. Imagine how difficult that decision would be for someone to make on your behalf when they do not know what you want.
I got these forms done up pretty cheap by a Vero lawyer named Darryl Jacobs. Look him up in the book. He's friendly and efficient. I guess this sort of paperwork is like an insurance policy...pay a little bit for it knowing that it could save you a lot of money in the future, but home that you never have to use it.