Bluffton Family Seafood House
I haven't tried the restaurant but have bought oysters and other seafood from Bluffton Oyster Co. and have always been very happy.
I don't know if it's shrimp season but their shrimp are also very good.
If you go to the restaurant you should check out the Calhoun St area and the market. There are some nice galleries and shops and the market is in a beautiful spot on the May River.