A funny and probably relevant piece from Joel Spolsky:
"Super quick review if you haven't taken any economics courses: econ is one of those fields that starts off with a bang, with many useful theories and facts that make sense, can be proven in the field, etc., and then it's all downhill from there. The useful bang at the beginning is microeconomics, which is the foundation for literally every theory in business that matters. After that things start to deteriorate: you get into Macroeconomics (feel free to skip this if you want) with its interesting theories about things like the relationship of interest rates to unemployment which, er, seem to be disproven more often than they are proven, and after that it just gets worse and worse and a lot of econ majors switch out to Physics, which gets them better Wall Street jobs, anyway. But make sure you take Microeconomics, because you have to know about supply and demand, you have to know about competitive advantage, and you have to understand NPVs and discounting and marginal utility before you'll have any idea why business works the way it does."