I agree with drkanchho. I agree that people who go for a postdoc get 35 to 45 k (depends on where you go). Starting salary of Assistant Professors in my univ (which is a state university) is 70 k. If you get a job outside academia it is even more. Let me give you an example of one of my friends. We did masters together. He did his PhD in molecular biology, did a postdoc for a couple of years and then got a job in industry. His starting salary was about 125 k. Two guys who finished PhD from my department got a starting salary of 90k (they did not go for a postdoc and applied right after their PhD). The salary depends on the field you are in, but still the starting salary will be more than 70k. It also depends how you sell yourself. Most of the time we undersell ourselves. I agree with guy_tensed that you may get a job with 50k with a Masters, but you will earn way more than that once you get a PhD. But on the flip side sometimes you might be overqualified for a job if you have PhD. It is your decision. Good Luck!

Sparty