Although this might seem trivial, it actually becomes in a ver distressing activity. This situation not only forces you to choose a professional path or specialization, but also requires you to define your academic career. In fields like Public Policy, the variety of options is huge and you can specialize in areas from Public Health to Economic Policy (and all the subareas within those ranges). Many people actually choose not to specialize and decides to go more broadly.
In my particular case, I was between choosing something more research oriented and something more practical. After taking different courses, I think I will let the PhD for the future and focus on practical policy matters. When competing with people like you, you also get to know where are your competitive advantages and what you really are passionate for.
At the end, my motive for pursuing public policy studies was to make a real contribution to practical issues that affect people in major urban concentrations. So I've decided to go for areas like Transportation and Crime Prevention in cities, from which I can learn from of the best professors in these fields.