I think the job market and pay rates depend on where you are geographically in the United States, and the connections you have or have the potential to make. As for Women's Health NPs versus Pediatrics, I would say take the middle ground and go FNP. If you then decide you want to specialize in either one you are totally set. Unless you are sure that you want to only work in pediatrics, or only work in women's health, the safest bet is to generalize your education and go FNP.
Careerbuilder.com has a place where you can view how much NPs make in your region. http://www.cbsalary.com/