I've lived in NYC in 75, 80, and 100k salaries and I've been fine in all cases. And that's without roommates and my SO being a student (so she can only contribute a bit for groceries, not rent). Rents are high, but so are software engineer salaries. Almost all of my friends who work in other industries make do with 50-60k salaries - we're fine.

If you really want to save, get a 2 bedroom apartment with someone. If they make >70k you will have a good amount of money for fun/saving/loans.