I agree with Anthony - average salary doesn't matter nearly as much as placement.
Most of the MIT MFin students are fresh out of undergrad and hence recruit for Analyst positions (banks would be silly to hire them as Associates, in line with +5 yrs more experienced MBA students). Also, MIT's website shows that the average work experience of 18 months includes internships and may appear high, as the program has a couple of more experienced people (30+ years old).
That said, among the best jobs people can get are the classic bulge brackets, prop-shops, MBB consulting and HF/PE. Banks and consulting firms pay $70-80k base for analyst - this salary is usually non-negotiable no matter what your background is. You will come by with $80k in New York, but it won't buy you everything. The real money comes two years later at an associate level where salaries will be $110-140k base + larger bonus. Switching to PE/HF at this point will be most profitable with an all-in comp of $250-350k (usually $125-150k base).
However, you will only have access to these top-jobs with a solid name on your resume. Mostly all PE/HF jobs go through headhunters which often exclusively recruit from top banks and top consulting firms (i.e., usually they will reach out to everybody in a BB's new analyst class). If you don't work at one of these target companies, you may reach out to headhunters yourself, but it will be much more difficult to get track. A middle market bank may lure you with a +$120k base salary upon graduation from your masters, but you will be way better off accepting the $80k offer you received from Goldman / JPM.
Think long term and hope for a $75k base starting salary. It will be your best choice - financially
