NPR's Planet Money asked Georgetown's Center on Education And The Workforce to compile a graph on how much money people with various college majors can expect to earn. This graph includes bachelor's and advanced degrees, so you can expect plenty of advanced degrees in medical preparatory programs because those include doctors. For the engineering occupations, a bachelor's degree is usually enough to earn that kind of money.
The clustering of the arts at the bottom is no surprise, as graduates with those degrees are taking a big chance at striking it big. A very few actors and artists will become fabulously wealthy in their field, while most will not. Meanwhile, engineers are consistently in demand.
Comparing the top to the bottom throws a spotlight on our priorities. If you have the know-how to extract another ounce of oil from the earth, you'll have it made. But if you want to teach the next generation, you might need to get a weekend job as well.
Planet Money contrasts this graph with an earlier one that charted only bachelor's degrees, in order to explain some of the differences. -via Digg
I've seen interesting stats come out of APS before, although that is specific only to mostly physics majors. Sometimes it also makes a difference to break down salaries into those fresh out of school versus those with experience. I assumed other professional societies in other fields try to keep similar records, but I haven't looked into it or noticed before.