All good points, Locrian. In my own case, this stuff really hit home when I ran into some old friends from undergrad right after finishing my PhD. They had both started working with Bachelor's degrees (and considerably worse grades and internship experience than I had when I finished my Bachelor's), and I'd just landed what I assumed was a very high-paying job. As it turned out, both of my friends were already making the same amount I was starting at, and furthermore had been earning substantial money during the 5+ years I spent in grad school on subsistence income. Which is to say that, unless my salary grows a lot quicker than theirs from here on out, I will *never* equal their lifetime earnings. Even my less fortunate friends, who earn less than I do, have such commanding leads in terms of money earned that it will take decades for me to catch up with them. Even though I didn't acquire any debt, there are many expenses I deferred because I couldn't afford them in grad school, and that now suck up my income (new car, dentistry, decent clothing, furniture, etc.) Fortunately, I did not go to grad school for the money...
That said, there are many important job aspects besides salary, and I win hands-down over my less-educated friends in those categories. This would be stuff like latitude in defining my own work, getting to work on interesting things, expanded career options, potential for advancement, stock options, and, let's not forget, a foot in the door of academia.
The point of all of this is that you can make decent enough money in most any career path if you apply yourself. The question you have to ask is what area interests you enough that you will actually be motivated to excel. Unless you're simply interested in maximizing your income with no regard for the quality of work, etc. Some people can cope with a career of drudgery if it makes them rich, but they're pretty rare. For the rest of us, I wouldn't base big career decisions on income, beyond ensuring that you stand to make enough to live a reasonable lifestyle (i.e., pretty much any career outside the arts).
