I find the case of Terri Schiavo heart wrenching.
Without taking sides, b/c I truly don't know and I find huge differences in the 'facts', I have been reading several commentaries.
Peaktalk has some good summaries; to me it is surprising so many fall (him in particular) on the side of Jeb Bush and the like.
In reading a little, for our mutual benefit, I am going to include a link here for Advanced Directives. You can create a handy-dandy print out this stuff out for yourself particular to your state and hopefully have some say if bad things happen your way.
I'll vouch for the fact that most of us have had our fill of bad things, at quota, thanks, but signing a form is a little thing to do to try to make something very wrong more right.
My only quandry right now is having an ex who would LOVE to have custody of his son...