Most of these beaches are ok but not beautiful enough to serve as justification for a visit to these places. Others of these beaches suck and I have no idea why they have all this fame. If you are already in some of these places, then visiting these beaches is better than nothing. One of these beaches is good but getting to it requires a day trip from a location with better beaches. If you are on vacation seeking beauty and you have limited time, don't waste it visiting these places.
Continental United States
Ok but not enough to justify a trip
South Beach, Miami:
This was the most disappointing. The beach suffers because it has this reputation as being so beautiful. The water is warm but not transparent. The tides are rough and there is risk of shark and jellyfish attack. If you are already partying in Miami, then visit. However, the beauty of South Beach does not justify a trip.
Virginia Beach:
This is actually nicer than most of the Floridian beaches but it suffers because the seasons. Clean but the sand and water are not transparent. Ok but not that good. You can only visit over the summer.
Jones and Lido Beach, Long Island NY:
These beaches are ok but only in the summer. If you are already near Lido beach, then they are worth it. The water is not transparent and is cool. The waves are ok but these beaches are free. These beaches are not as good as Virginia because you cannot visit at all in the winter.
Malibu, Manhattan Beach, Hermosa Beach, Southern California
These are the lowest level beaches that barely make the grade. If you surf, you may have a different opinion. But if you enjoy white sand, black sand, and blue water, then you won't like these beaches. The water is too cold all year round. Even surfers have to wear body suits in this water. In the summer after a good sweat, getting into this water can be refreshing, but these beaches suffer from cold water all year long, opaque water, and brown sand.
Terrible
Northern California, Zuma Beach, LA, Rhode Island, Venice Beach, LA, Santa Monica, Jersey Shore, and special overrated, terrible status for The Hamptons.
Don't even bother with any of these beaches. All of the beaches in Northern California suck. The water is cold, the sand is dark brown, and there are dangerous riptides. I went in because I love beaches, but all of the beaches near San Francisco are just horrible.
Zuma Beach is cold, full of seaweed, and the water is completely opaque. It's somehow worse than Manhattan Beach, Hermosa, and Malibu. I couldn't even stay in the water because it was just too cold.
Venice Beach and Third Street Promenade are cold and dirty.
Jersey Shore. I like Jersey and I have lived there for 20 years. These beaches suck. You can only visit over the summer. The water is polluted. The sand is nasty and the water is cold all but two months a year. Also the Jersey Shore is full of dangerous riptides. Somehow the Jersey Shore is worse than Long Island with one notable exception.
The Hamptons:
Southampton, Northampton, whatever: these beaches are the worst. The water is cold and opaque; and all but two months a year it's too cold to even visit the beach. But even worse than the Jersey Shore, there is not even sand. The sand is just rocks. You have to wear shoes on the beach to avoid cuts from the damn rocks! Who knows if there are needles in the water, it's completely opaque. Even worse, is the Hampton's unfathomable reputation as a place where the beaches are good! I don't know who started that rumor but these beaches suck!!
Mexico
The only Mexican locations worthy of mention as part of the best in the world are: Isla Mujeres, Cozumel, Holbox. These aforementioned locations are worthy of listed alongside Antigua, Grenada, and some of the second best in the Caribbean.
OK but not enough to justify a trip
Isla Contoy:
This beach is ok but when compared to Isla Mujeres was disappointing. It is probably better than most beaches in the continental US but it was not as good as Isla Mujeres or even Cozumel or Tulum. Not terrible and there are other reasons to visit Isla Contoy. My issue was that getting there required a day trip and so I spent an entire day waiting for this beach when the beaches on Isla Mujeres were so much more beautiful. Nevertheless, it might have been worth it. I thought that a secluded island in the Caribbean might just be where I could find the world's best beach and in this case, I was wrong. Don't make that mistake.
Playa del Carmen:
None of the beaches here is sufficient justification for a visit: water is not transparent, rough, full of seaweed, and expensive. Just go to Cozumel. If you are there for Spring Break or some other reason these beaches will do, but if you are looking to find beautiful beaches avoid this place.
Beaches that Suck
All of the beaches on the Pacific. Baja California, Ensenada, Acapulco, Cabo San Lucas, and Puerto Vallarta. None of these beaches is any good. The water is cold, not transparent, and rocky. Really from the San Juan Islands up in Washington State down to Cabo all of the beaches suck. The water is freezing cold with dark brown sand, dangerous riptides, and dangerous rocks. These beaches are good for surfing. Might be great for surf but if you enjoy swimming, lazing around, etc., they suck.