Among New England states, Rhode Island, the Ocean State, has a reputation for great beaches, but in fact all of the New England states except Vermont have good ocean beaches. (Vermont has lake beaches.)
Rhode Island
Rhode Island's beaches are either facing Long Island Sound or on Narragansett Bay, which also provides some protection.
Among the favorites are Charlestown's East Beach, Newport's Easton's Beach, and Narragansett Town Beach in Narragansett.
In South County, the big Misquamicut State Beach in Westerly and the several beaches in Watch Hill are great. On Block Island, Sandy Point is the choice.
Connecticut
Connecticut's Shoreline beaches have some of the warmest water because they face Long Island Sound, which protects the shore from the force of the Atlantic. More...
Massachusetts
Massachusetts has all those Cape Cod beaches (including Cape Cod National Seashore), as well as others on the South Shore near Plymouth, the North Shore and Cape Ann, and the islands of Nantucket and Martha's Vineyard.
New Hampshire
New Hampshire has long, fine Hampton Beach, as well as the beaches on its lakes, particularly huge Lake Winnipesaukee.
Maine
Maine's best beaches are along its southern shore, south of Portland, but there are others all the way to the Canadian border (especially around Acadia National Park).