Anything naturally grown. Fruit digests better alone, so I would eat this first, as opposed to dessert, like is customary with some. Vegetables are good (more nutritious) raw (depending how an individual tolerates them), steamed, or steamed and mashed. Of course, smoothies could work also, plus you could actually mix fruits with greens. Having lots of different colors of food on a plate is also a good idea- different colors are attuned to different systems in the body. Breads and the like would be best homemade; or buy an expensive good loaf with limited preservatives, unhealthy oils, etc. Crackers and muffins are really easy to make, and bread really isn't that hard, either.
Well, those are some suggestions. Mostly, have fun, make meals with a loving attitude, get the older kids involved- those sorts of factors just can't be found in a pre-packaged meal.