O.k, I admit that it is worth staying in this place at least…a lifetime, it`s beyond any doubt, but if you have only 24 hours at your disposal, let me give you a complete list of things to do, so that you can pick up the taste of the dolce far niente, typical of the island life, of the discreet tempo and of the unique shades of St.Barths:

8:00 a.m - breakfast on the sea shore+champagne, it`s a must (yes, you can, you must, it`s compulsory here!)
9:00 a.m - simple and unforgettable: sunbathe and go for a swim in the azure water –believe me, it seems ordinary, but such a gorgeous azure&setup are hard to find in other corner of the world.
12:30 p.m - a delicious&extravagant lunch on the beach, because everything happens, lives HERE!
14:00 p.m - a walk through Gustavia, the capital of the island, crammed with boutiques and chic hotels-careful, you shopaholics!
17:30 p.m - a cruise at sunset with a glass of champagne in your hand (yes, again)- so that you wouldn`t get out of practice and spoil your fun. Hey, we`re on vacation, aren`t we?
19:00 p.m - the evening goes on to the same rhythm, with a relishable cocktail.
22:00 p.m - Le Ti Restaurant, for dinner and dancing, to finish the day with 100%  St Barths vibe.