Help with school lunches?

School is in full swing. What do you do when you have a picky eater? I sure would love some suggestions on what you pack for your child for lunch. Leave some comments, and I will update this post with your suggestions. Maybe we can all help each other out? 

Right now these are the items that she likes and would like to take to school (not all at once): cubed cheese, fruit slices, flour tortilla with cheese (she is not a big meat eater), crackers with cream cheese, jelly sandwich (she does not like peanut butter), boiled egg (rarely but sometimes she will eat a boiled egg), pistachios or cashews, loves Lima beans and mac n cheese (items to keep a thermos warm by lunch time?), candied carrots, yogurt, sometimes will eat chicken nuggets (again, how to keep warm?), sometimes chips, and a bagel with cream cheese.

So any ideas on food, and help to keep her thermos nice and warm by lunch?