Anse Colombier - perhaps the nicest beach but nothing there - no chairs, restaurants or other amenities. The beach is considered crowded when there are more than 10 people there!
Anse a Flamands - some restaurants/bars, I don't recall seeing rentals for the beach.
Shell Beach - upscale bar + restaurant. I believe that they have chair rentals as well. Bring the title to your house along as collateral
Gouvernour beach - parking is close by, but no amenities