If you mean specifically at the parks....all restaurants except Emeril's give a 10% discount on food and non-alcoholic drinks. This also applies to character breakfasts. Also it's generally 10% off merchandise throughout the park.
We found the only place apart from those mentioned were the carts . We bought or had the souvenier refill cups which we had filled with water anyway so we didn't need to use AAA at the carts anyway!
think the only places that won't take AAA is the restort restaurants, Buba Gumps and Emirls besides that the rest of them will give you 10% off and don't forget about the shops also give a 10 % with AAA card.