Karen-
There is an enormous range of opportunity within the field of public health! To begin with, an MPH degree will give you a much better overview of the healthcare system of this country, plus studies in a wider range of areas that apply to medicine: academic research, analysis of research publications, healthcare policy and management, international health, environmental or occupational health.
If you are interested in international health and working abroad, an MPH will assist you greatly as the public health world has a wealth of connections with the very best international health and medical organizations in the world.
It's true that an MPH is useful for both academics and administrators, but I would argue that it is useful for everyday clinicians as well. Like it or not, our country is moving towards population-based medicine, with managed care, capitation, and enormous pressures on social programs such as Medicare/Medicaid to produce maximum benefits for maximum numbers of people.
If you want more information, visit
www.asph.org to learn more about accredited schools of public health. That isn't to say that a non-accredited program won't be useful (many combined degree programs aren't ASPH or CEPH accredited) but it should provide you a good base of knowledge on your decision to pursue public health. Good luck!
