Such a broad question without knowing with kids/without, want characters or not, ambience/experience over food quality or other way around, etc. Are you staying on property and can get around easily?
Breakfast: Kona is top priority and a must do on every trip we make.
Dinner: Many have mentioned these but for the " Disney experience": Whispering Canyon, Be Our Guest ( Lunch Only), Skipper Canteen, Tusker House, 50S Prime Time, Beaches and Cream, Ohana, Land Grille, San Angel.
For the food: Yachtsman, Flying Fish, Jiko, Narcoosees, Cali Grille, La Hacienda, Via Napoli or Tutto Italia, Boathouse, Raglan Road, Boma, Artist Point.
For adults Lounges: Nomad, Sams, Jock Lindsey, Geyser Point, River Roost ( and you get Bob), HBD Lounge, Raglan Road, Rose & Crown, Tutto Gusto.