The people who make the most don't work, they make money from their investments. The highest paying careers are in Business, Finance, Marketing; Sales ( there are no guarantees in life, but if you're good you can make mega-bucks) - I've learned it's best to go where your heart is.
depends on your definition of rich. Do you monetarily or a richness in experiences. For the first, go into chemistry and work on alternate fuels, the later, pick a humanity where you can help people that need it. You choice on which "rich" you'd rather be.