In this month's issue of Employee Benefit Advisor magazine (a trade journal for us health insurance geeks), business journalist Maggie Mahar posits that, when it comes to the current state of health care, there's plenty of blame to go around. She's written a book on the subject, which link I'll post when available.
In the meantime, I found these charts to be quite helpful in assessing just how much each facet of the debate bears on the total (I make no personal claims as to their accuracy):