I highly reccomend the laptop lunch system. We got one when our son started presechool and by the end of the year nearly 3/4 of the class was using them. Shop around you can usually find coupons or sales.
http://www.laptoplunches.com/
Their site has great lunch ideas too.
Typical lunches for my at that age were:
avacado rolls
dumplings
edamame
hummus
carrots
laughing cow cheese
apple slices
graham crackers
hardboiled eggs or deviled eggs
cut up strawberries w/ yogurt dip
wholewheat crackers
cheese stick
grilled cheese sandwich
banana
cookie (they could have sweets one day a week)
pinwheel (rollup) sandwiches-tuna salad, egg salad, chicken salad, roast chicken, roast beef etc with ranch dressing and cheese
chips
mixed fruit or berries
Follow Mothering