The Giant Dipper coaster looms over the 91-year-old, mile-long Santa Cruz (Calif.) Beach Boardwalk. (1992 file photo by Elizabeth Rowland)

From toddlers to grandparents, everyone loves to stroll the boardwalk, where people-watching is a sport and games, rides, taffy and fries amuse active vacationers. The classic gray, weathered planks are disappearing as beach towns replace high-maintenance wood with more storm-resistant concrete, says Stephen Leatherman, director of the Laboratory for Coastal Research at Florida International University. As "Dr.Beach,'' he issues yearly ratings of the USA's top 10 beaches and runs www.topbeaches.com (his self-published America's Top Beaches, $19.95, is available only from the site or by calling 888-867-2322). Here are the doctor's prescriptions for primo promenades:

Atlantic City, N.J.- The mother of all boardwalks, dedicated in 1870, began as a one-mile strip designed to keep sand out of businesses and railroad cars. Today, the four-mile gangway of glitz, with its 11 casinos and Miss America Pageant, is an international landmark. "You'll never see another spectacle like this,'' from the 100-year-old 2,000-foot Steel Pier amusement center to Donald "Trump's pink and purple Taj Mahal, look(ing) like something out of the Magic Kingdom.'' T he casinos have entrances right on the boardwalk, "so you can step off and have a $100 lunch'' or just grab a hot dog on the boards.

Ocean City, N.J.- Built in 1928, this 2½-mile elevated boardwalk is "a remarkable memory magnet'' for parents and grandparents. There's the Wonderland amusement park, with its giant Ferris wheel 140 feet above the boardwalk; the recently restored 1926 Flanders Hotel, one of the few remaining old-time hostelries on the Jersey shore; the Moorish-style Music Pier, home of the Ocean City Pops Orchestra; and lots of miniature golf.

Ocean City, Md.- An open "train'' ferries summer visitors along this cheerily honky-tonk three-mile promenade. The south end is anchored by the 109-year-old Trimper's Rides, which includes a 1902 carousel and the venerable Zipper roller coaster. Arcades feature old-fashioned pinball and claw machines, along with their high-tech cousins. Souvenir shops, carny booths and bars dot "the tacky scene.'' Stands serve local favorites like Thrasher's vinegar-soaked fries.

Virginia Beach, Va. - The newly renovated concrete boardwalk, a three-mile descendant of the four-block wooden one built in 1888, has plazas with roving entertainers, three oceanfront stages and a separate path for cyclists. Plantings and seating areas create a "congregational'' environment, and you can watch "cruisers and huge aircraft carriers from the Navy base in Norfolk right offshore.'' Museums include the 1903 Old Coast Guard Station; the Atlantic Wildfowl Heritage Museum, housed in the boardwalk's last remaining oceanfront cottage; and, 1 ½ blocks inland, the new McKee's Beatles Museum.

Myrtle Beach, S.C.- The birthplace of the shag, a jitterbuglike dance popular in Southern coastal towns, "has popped up like a mushroom. Twenty years ago almost nothing was there but an old wooden boardwalk.'' Now home to scores of golf courses and country-music dinner theaters, Myrtle Beach retains the soul of '50s Americana (and a few blocks of a concrete and wood walkway) on its two-lane boardwalk, a.k.a. the strip or the boulevard, which people cruise by car. The Pavilion, a 50-year-old amusement park, is famous for its Corkscrew roller coaster, and The Family Kingdom has the Swamp Fox, a classic wooden one.

Miami Beach, Fla.- "South Beach isn't a true boardwalk, but it's the hottest beach (promenade) in the country, with models and trendy cafes'' {ndash} and tourist-jammed sidewalks. A couple of miles north of the town's hot spot, however, is a real though little-known boardwalk: a relatively new, wooden one just under two miles long. A scenic promenade along the wide beach, with railings and seating areas, it's to be extended next year. "The boards run in the direction you walk rather than crossways, and that's nice because it keeps the in-line skaters off'' (they'd get stuck in the grooves).

Rehoboth Beach, Del.- One mile long in a one-mile-square "town'' that began as a Methodist camp meeting ground in 1873, the elevated wooden boardwalk reflects Rehoboth's dual nature as a family-oriented resort and a mecca for gay beachgoers. Among its landmarks are the famous saltwater-taffy palace Dolle's Candyland and Funland, a small, family-run amusement park that dates back to the '30s. Several kiddie rides there still cost only a quarter, with "adult"" rides 75 cents to $1.25. The boardwalk begins at a turnaround on Rehoboth Avenue, where a band shell adds nightly concerts to the entertainment mix.

Long Beach, Wash.- At the south end of this 28-mile beach is an elevated wooden walkway, built in 1990, that runs about ½ mile across the dunes. "They have hard-packed sand there, so strollers can watch races, clam diggers, sand-castle contests and some of the best kite-flying in the country.'' About 120,000 people are expected for the 17th annual International Kite Festival Aug. 17-23. There's "a steady on-shore breeze and no humidity, so you never feel hot even on a 90-degree day.''

Santa Cruz, Calif.- "The most famous boardwalk on the Pacific coast'' is a great vantage point for watching the many surfers drawn by the big but relatively safe waves: "The beach faces south, and the mountains are to the north, so a lot of the winter storms are blocked.'' The mile-long, 91-year-old Santa Cruz Beach Boardwalk amusement park features 30 rides, including a rare 1911 Looff carousel and the 1924 Giant Dipper wooden coaster, both National Historic Landmarks. The Dipper's 70-foot ascent affords a grand view of Monterey Bay. There are free Friday-night concerts through Sept. 4 at the beach bandstand.

Newport Beach, Calif.- This wealthy enclave south of Los Angeles, with a harbor that"s home to more than 9,000 private yachts and boats, boasts a "definitely upscale" 2½-mile boardwalk. Instead of games and amusements (they're on the bay side), the concrete promenade bears strollers, cyclists, skaters and runners. It's "quite a scene: a city beach, but not out of control like Venice Beach." Restaurant parking lots are "full of Jaguars and Lamborghinis, but you can still get a good fish dinner for $30 right on the beach.''