Difference between rent and mortgage: 248.7% Boston is perhaps America's biggest college town, with more than 100 schools and more than 250,000 students. Best known as the home of Cambridge's Harvard University (19,900 students) and the Massachusetts Institute of Technology (10,900 enrollees), Beantown also hosts Boston University (32,400 pupils), Northeastern University (19,700 attendees) and other large schools. Add in a fairly strong local economy and you get a hefty $3,084 average asking rent. That's more than enough to cover the $1,240 monthly mortgage bill you'd face on a home with the Boston market's median asking price of $334,900. "Boston is a large urban center with lots of institutions of higher learning, so investors will find great opportunities in the rental or resale markets," DuBois says.