J.C.
It all depends on what you're looking for. The beach is perfect for just sitting and relaxing all week, and children LOVE it! If you can swing it, go to a resort close to the beach so you can either hang at the resort pool or lazy river, when you're tired of the sand.
But if you're looking for more of a "doing" vacation, Cincinnati is a great place - lots to do for every age. The Museum Center is great, for getting out of the hot sun, plus the Newport aquarium, lots of great parks and gardens, downtown shopping, King's Island, water parks, etc.
The mountains are also great, if you like camping or can at least rough it in a cabin. Olgebay's not too far. Or Hocking Hills.
Or if you have lots of money and can fly across the country, I'd vote for Seattle! That's where we are going next year.
Good luck! J.