Our standard list is includes:
Peanut Butter Sandwiches or Fluffernutters Sandwiches
Jalapeno Cheese Crackers
Fresh Fruit and/or Dried Fruit depending the season
Honey Stinger Bars or Power Bars
Cashews or Peanuts
Chocolate (bars or raisins)
Water and Gatorade
On our winter trips we take the JetBoil for coffee, hot chocolate and cup of noodles to warm up.
We've taken dinner leftovers a few times: cold pizza and a cold burrito (didn't appeal to me too much).
We always manage to take plenty along and bring something back. Don't want to get bonked on the trail at the end of the day.