Rockley Beach is my favourite. I know it's the far side of Bridgetown from the cruise terminal so it's quite a way to go, but it's worth it in my view. That also means you get far less cruise passengers so it tends to stay quiet even when their are ships in port. You have the Tiki Bar on the beach and you have Chefette & Barbeque Barn just across the road, or Quayside just 2 minutes walk away. There are some beach huts selling food/beverages/local goods too, there're decent toilets on site. You can hire chairs for BBD$30 for two if memory serves, we don't normally bother with a brolly as we like to sit under the trees. What's not to like?