We always go to Le Cellier at least once during the trip because it's our favorite restaurant. We usually try to squeeze in 1 Beaches & Cream, 1 Kona Cafe for lunch, and we always have to have chicken strips, preferably at a resort because then I can load up on pickles and onions. We usually try to have at least 1 new restaurant to try - last trip Cape May for dinner was our new restaurant. This September, we'll have Teppanyaki and 1900 Park Faire as our new places. It does get harder to squeeze in the new restaurants though, because we all have our favorite must-dos. For DS1 it's Trail's End and Boardwalk to go, for DS2 it's Le Cellier and Sci-Fi, for DH it's Le Cellier and Cantina de San Angel, and for me it's Kona Cafe for lunch and Tomorrowland Noodle Station.
I don't know what it is but I honestly really really like the chicken strips that WDW has.