I haven't weighed in on the Schiavo case (and I won't call her Terry--it's infantilizing and overly familiar. more thoughts on a related angle here), mostly because I thought it would be useless. People have already made up their minds.
But I do wish to come out in favor of permitting spouses, not parents, to speak for us when we cannot speak. I am not coming out in favor of "killing brain-damaged people whenever their spouses think they would want to be killed," but I am arguing for meaningful agency. When we marry, we break the bonds of the family into which we were born and legally register our intention to establish a new next of kin: one we choose. We choose someone who relates to us not as a parent, with all the tendencies to ride roughshod over childrens' wishes that years of dependency and paternalism imply, but as one free adult to another. There has never been any proof that Schiavo's husband lied about her wishes, and for better or worse, no matter what kind of a person he is, he is the one she chose to convey those wishes to the authorities so she could die as she desired. Refusing to listen to her husband on the basis of ad hominem attacks that have no bearing on the accuracy of his testimony is repellent and undermines the dignity of Schiavo's choice to marry, as well as her choice about how to die.
This is especially meaningful to me because I am afraid of what would happen to me if I were in a similar situation. My mother, at present my next of kin, has told me many times that she will disregard my clearly expressed wishes about bodily integrity if I am incapacitated. A living will might help, but unless it's found before she is contacted, the window for making sure it is my wishes which are acted upon and not hers may pass.
Birth is an accident. Who you bind yourself to in the future, and your beliefs, are freely chosen. That parents can forever own the lives of their children, despite clear actions that establish an intention to enter into a mutual relationship of agency with another adult, is deeply offensive to notions of personal sovereignty and independence.