The Wrightsville Beach area is very nice. Kure Beach might be the prettiest beach north of Florida, but I recall that for the most part swimming is restricted because of undertows.
My favorite beach in the eastern USA is Captiva. Being on the Gulf, it gets those amazing sunsets over the water.
I remember as a small child being afraid of the "under toad" in the water at Kure Beach and Carolina Beach. They both have built up quite a bit in the past decade, pretty upscale now. They were once regarded as the blue collar beaches, back in the fifties and sixties, cheaper accomodations, cheaper restaurants.