We intentionally chose a center that DIDN'T provide lunches after visiting one that was serving complete junk...
We try to keep lunches as simple as possible to help us get them made and out the door. We pack the night before. At our old center, we put an ice pack in the bag; our new place has a fridge.
Generally, we pack a protein, a grain, and a vegetable (sometimes a fruit, but they seem to get lots of fruit during snack time.) For the protein, we send beans, chicken pieces, organic lunchmeat turkey, Quorn nuggets, or hard boiled eggs. The grain is usually whole wheat pasta, brown rice, or whole wheat pita bread. Veggies are whatever is left-over, or we thaw and cook a small portion of frozen veggies - peas, peapods, broccoli, califlower, sweet potato, squash. Our old place was peanut-free, so we haven't gotten into the peanut butter sandwhich habit, but once in a while we do that. Also, a lot of kids bring baby carrots, but our daughter doesn't seem to like them very well.
i hope this helps -