<p>On average, a JD makes more than an MBA, but that' mostly due to the fact that there are lots and lots of mediocre no-name MBA programs out there. There are also mediocre no-name JD programs out there too, but I doubt that there are as many as there are MBA programs. Hence, the average MBA salaries get dragged down by all the mediocre MBA's. </p>
<p>I agree with calipharius in that it is highly contingent, especially on the industry that you choose. If you just want to make lots and lots of money, go to investment banking. However, most MBA's, even at the top schools, do something else besides investment banking. In fact, many will choose less remunerative industries because of a higher quality of life or other factors.</p>