Mine actually looks fairly legit...
Boston-Cambridge-Quincy, MA-NH HUD Metro FMR Area (MA)
One Parent, One Child
Monthly Housing $1444
Monthly Food $369
Monthly Child Care $1019
Monthly Transportation $480
Monthly Health Care $1037
Monthly Other Necessities $464
Monthly Taxes $722
Monthly Total $5535
Annual Total $66419
Rent listed here is a couple hundred too high, and food maybe $70 too high, but higher childcare costs more than make up for it (and thank goodness little on is in preschool now - infant care much more expensive!) Transportation budget here is hefty, but I'm used to my bus pass, so may not be the best judge. Other Necessities seems a bit high, but counting utilities, clothes for the little one (who grow like a weed), student loans (which ok, maybe shouldn't be counted in this category) - it's a bit higher than mine, but not laughably so.
As I understand it, health care costs, including employer contribution usually run around $10000 for a family like mine, so the cost here is only about 20% too high.
All in all, modest might not be the best word, but excluding transportation (as I said bus pass, which I know many folks in my area consider a few rungs below modest!) and healthcare (not sure of exact figures), I'm probably within a couple hundred or so, so this seems like a fairly reasonable estimate.