A single person can live reasonably well on $75,000. A family needs closer to $140,000 to maintain a good standard of living, factoring in childcare and increased housing costs. These numbers assume some level of eating out and entertainment, but not excessive spending. Housing costs are the biggest variable, so research neighborhoods carefully.
honestopinion: It really depends on location; $75k might be tight in Manhattan but comfortable in many smaller cities. Families definitely need more cushion, especially with kids.