I lived in Biloxi for several years. If you are going down there for the beach...don't. The beaches are awful: brown water, no waves, calf deep as far as you can walk, bad pollution, especially after it rains. If you are set on going, Ocean Springs has the best of the beaches unless you want to take the ferry to Ship Island. It's a long haul but might be worth checking out.

There is great fishing in the area.

Now, the food in the area is as good as the beaches are bad. Skip Mary Mahoneys. It has coasted on its reputation for years and was hit with felony charges for misbranding seafood from Africa and India as fresh from the Gulf. Also skip The Shed BBQ. It is terrible. Murky Waters BBQ is much better. Some of the best spots to eat are:

The Blind Tiger
Steve's Marina
Jourdan River Steamer (middle of no where but come hungry)
Brooklyn's Pizza
Samurai Sushi
For a Fancy Night Out: White Pillars, Vestige

Not sure if they still do it but Miss Audrey's Southern Kitchen used to do an all you can eat seafood buffet on Friday. Holy mackeral that was good food.