Study whatever the fuck you want to study, but please don't go for research field (especially Biological science, Physical science,Physics, and all those nonsense courses). You will die studying and won't be able live your life. I felt like I made a big mistake in my life so I am taking a completely different direction now. I am starting a new career with my own business ventures even after getting a PhD. I don't regret much for having wasted my time coz I have become more analytical and more capable of taking judicious decisions for myself, but life would have been much easier had I taken a different route earlier in my life.
My suggestions:
If you are really smart and hard working, study Dentistry, Medicine or even Law from good schools in the US.
If you are an average student and not so capable of taking the risks, then IT, Computer science or any engineering field is a good choice.
If you are an average, below average student, but street smart type, then study Management, finance, Political Science, International relations ( I should have gotten myself this degree and regret now for not doing this) etc.
All other degrees are worthless if you really want to see yourself as a happy individual and be able to get settled early in your life.
However, beyond all, you must do something that you would feel like you would pay someone for asking you to do what you need to feed your family. You must love your job for the rest of your life. So please be wise now than regret for the rest of your life.
Or if you are a risk taker and genuinely smart, you can simply get an undergraduate degree in management/business and start a hot-dog stall at one of the busiest streets in New York. I am damn sure you will end up being bigger than those Wall-street'ians and will achieve more than any other career professionals would achieve. 
Summary: Smart people would waste no more than 16 years of their life in school!
Good luck!