Most of the major chain hotels (Hilton, Marriott, Hyatt, Sheraton, Holiday Inn, Choice, etc) have AAA discounts, as do the WDW resorts (discount is either 15% or 20%). Example, AAA rate for Embassy Suites Lake Buena Vista is $99/night (taxes not included).
As for restaurants, I know that the Landry chain of restaurants (e.g., Crabhouse) give AAA discounts (either 10% or 15%--but I think it is 10%). Also, AAA discounts (10%) are available at the restaurants in Universal Studios Florida and Islands of Adventure.
I find AAA membership to be of good value.