That's dependent on your lifestyle, amount of debt and expenses. It's hard to imagine less than 1 million in insurance. Possibly more. However, the working spouse should always maintain insurance on the stay at home parent, since there not going to quit their job to replace the deceased stay at home spouse. And the cost for a full time nanny and or day care can be very expensive.
The best solution for the majority of Americans is an inexpensive term policy for the proper amount after the expenses and financial profile are properly evaluated. I would suggest working with a financial planner who is not commissioned based that can give you an unbiased opinion before you speak to an agent about the proper amount of coverage.