I don't understand why you are so concerned about state tax rates when cost of living will have a drastically higher impact on your economic status long term. If you have to choose between a city has a 10% tax rate, but is 25% cheaper than 'Metropolis' with a 5% tax rate, the math is simple as to where to locate.

Heck, if you're at 8% in NYC, move to a different city (pick any) with a lower rate by any amount. That, coupled with the lower cost of living will free enough money to send your kids to a private school. See math for Miami below, my recommendation.

Regardless, Florida is the obvious answer. Am I missing something- why has it not been mentioned? No income tax. 6% sales. No better weather in the US, plenty of outdoor/unique outdoor activities, Miami is progressive and has a massive Oneworld hub. Incredibly close to amazing vacation destinations. Private schools just as good as most major cities in the US.

To enforce my first point, Numbeo says Miami is something like (just averaged each line item together) 30% cheaper than NYC. So... if you're making 200k, we are talking tens of thousands of dollars, not to mention a 8% tax savings. As a guy that went to a great private school in the Midwest, thats enough to send all your kids anywhere. Not to mention profit from real estate.