How much money would you have to make for it feel like you weren't just scraping by? Would about half a million dollars a year do it? Well, think again: The economic geniuses running a website with the highly trustworthy name "Financial Samurai" did the math to prove that a family of four living in Manhattan would barely survive on $500K annually. No, really.
Read the (horrible) blog post if you must, but also, you can easily get the gist of its (very bad) argument by looking at the chart that appeared with it.