Margarita Island, or Isla Margarita, is in the Caribbean and part of Venezuela. It is particularly popular for package holidays, and there are many all inclusive resorts and hotels to cater towards such package vacations. There are regular charter flights from Europe in particular, and Isla Margarita is popular for a week long beach holiday.
The beaches are great and tours can be arranged to highlights on Venezuela's mainland such as Angel Falls. Many of the hotels and resorts have casinos attached and the vast majority are all inclusive. In fact there's so many resorts on Margarita Island, we won't even begin to attempt to start reviewing them - they are, by and large, all rather similar luxury resorts. For those looking for a boutique style, small and slightly quieter hotel I'll throw the name of Posada Caracol at you - it's a peaceful small hotel with a lovely swimming pool, 30 minutes from the airport and main tourist town of Porlomar.