Should someone that is studying accounting go for a CPA or for a Masters degree instead? Which one is best to have?

If you want to become a Professor please go for Masters Degree. Vision makes everything directed and for the decisions. Sometimes it could be the available opportunities in the nearby proximity. 

I AGREE WITH MR VENKITARAMAN ANSWER  

In my opinion the qualification to attain should depend on the reputation and acceptance of the qualification in your country and internationally. Next the cost of the qualification may be considered depending on your affordability.

The Accountant is like a driver and the qualification is like the driving license. The driving license is indeed an important certification of the fact that you are a driver. Once you receive your license, what matters is your experience as a driver.