Is there a report that shows the families who have spent the most money with us? Our top customers?

You can report on your top customers using SearchTransactions from the Transactions menu. Define a date range you would like to see your top spending families for and then use the Special Search criteria Top 250 Customers By Date Range

This report will display up to 250 customers, ordered by the total amount of payments they made to you in the date range you specify.