Musts:
San Angel Inn dinner (I always get the Carne Asada)
Pecos Bill lunch (We split a salad and a fajita plate...simple and delicious)
Tusker House Breakfast (Not usually a fan of breakfast buffets, since I don't see the value in paying buffet prices for what amounts to cheap American breakfast food, but there are enough unique and tasty offerings to make this place a must-visit)
Flame Tree BBQ lunch (We order lots of chicken. It's tasty and the protein fills us up for a while)
Cape May Cafe dinner (We pretty much just try to eat our weight in crab legs)
We have relatively simple tastes, and usually prefer the quick service meals to allow more time walking around the parks.