What are the best beach towns to visit and their accomodations?
What part of Europe? Are you looking for warmth and sun, or are you trying to escape the heat of summer? As I usually fall into the latter category, I like De Haan in Belgium and Domburg in the Netherlands.
I think it's foolish to go to Europe for a great "beach" experience. Sure there are beaches in Europe, some of them quite pleasant. But they are not the "dream beaches" that most Americans pine for. Most Americans want uncrowded, broad swaths of white, fine-grain sand, with room to stretch out. Most European beaches are quite different from that. Often pebbly, often crowded, often privately owned, often lined with chaise lounges that you rent by the hour. Not always all of these things, but most often at least some of them. If you want a great "beach experience", Hawaii, Florida, So Cal or the Caribbean are a better bet. That said, there are certainly lots of pleasant places by the sea to spend time in Europe. Just calibrate your expectations accordingly.
I have actually rather enjoyed some of the beach towns I have visited in Europe. I think you posted another question so I assume you are asking about France. There are two that I like there... one is St. Maxime's which is a fun beach town with lots of nice restaurants, shopping and a market. Also, a carousel on the beach which is fun. The other is in the Carmague and it is Ste. Marie de Mer. Not only is the drive there interesting it felt like exactly what I imagined a french beach town to be (whatever that is).... Anyway, if you go there with any luck you will also so the white horses and pink flamingos.
THE best beach town is Warnemünde and there is plenty of affordable and nice, charming and traditional accommodation. Also it's a very popular port of call for Baltic sea cruises and all major cruise companies visit. Yet it's surprisingly inexpensive.
Hopefully I'll get to go to the beach more often this summer! I really liked Cassis near Marsielle in Provence, France. On the west coast, St. Malo doesn't really seem like a beach town but there are nice sandy beaches in town and the water was surprisingly warm, despite being on the English channel.