I was excited when I read your post because I knew I'd get more ideas for my own child from your responses. I'll ad some of what I do for my kiddo that wasn't mentioned.
An extremely RARE treat I send with my little girls for lunch maybe once or twice in a school year is:
that whole grain white bread with
Nutella spread on it.
This amounts to a "chocolate sandwich". No messier than PBJ and it's SUCH A TREAT that my daughters are instantly delighted and have bragging rights for lunches for the rest of the school year. LOL Nutella is sold in grocery stores usually same isle as peanute butter and often right beside it or very near it. Small squatty plastic jar-current white label. It's made from Brazil nuts and does have cocoa in it. It's definately fatty but like peanute butter isn't going to harm your kiddo or hock 'em up on sugar. Plus your kids will always think you're the absolute best 'cause how many kids get a chocolate sandwich??
I find I don't have lots of time to put together stuff and the thermos idea obviously works for some but it won't with mine. If it can make a mess or spill IT WILL and usually ALL OVER MY KID or the rest of their lunch which means stains-soggy food or at the very least a mess to clean up for the teacher/ caregiver or me. SO I AVOID thermos stuff like the plague. I also read a recent article in Good Housekeeping that tested thermos bottles that come with lunch boxes and their findings showed that few keep things warm enough to call it warm or protected enough to prevent spoilage which is the whole point of using a thermos. There was a list of thermos included that met safe standards and it can prob. be tracked down through Good Housekeeping's website for anyone who is interested including you if you like. Me-I won't bother.
Instead I like the cold/ room temp. route.
I LOVE love love those gel packs or cold shapes that you freeze that do not leak or spill and can be reused. I put one in almost every lunch and my kids leave it-they never take it out. SO it keeps the sandwich cool-the juice box or pouch cool-the fruits-yogurt, etc. nice and cool. An added bonus is that if any boo boo occurs there's a handy ice pack nearby both at school-in vehicle and at home that doesn't melt into a puddle.
I just wash 'em with warm-soapy water-swipe a towel over and toss back in fridge. I keep several on hand so that there's always at least two frozen-one for each child in home. You can even layer the foods in a lunch bag with multiple of these if you feel it's necessary.
I have always been picky about my own foods and hate soggy sandwiches so I pack lettuce and tomato seperate to be added when it's lunch time.
Simple nachos are something that works well too! A healthy take is the baked Blue corn chips, shredded cheeze-tomatos-little sour cream-and guacamole or chopped avacado pieces. FOr those spicy kid lovers you can ad some salsa and include some canned beans or bean dip etc.
Little containers work great and I like the "disposable" snack cups with lids and I reuse them by washing in dishwasher top rack or sink. (AVOID heating foods in plastic to prevent dioxins from leaking into foods-these are linked to all sorts of health issues including breast cancer causes. This is the BPA FREE trend and reason that recyclable grade 1 and 2 plastics are considered safest.)
A slight change since sandwiches DO get somewhat boring is to change out the bread.
I have used dinner rolls, cresants, and biscuits with whatever between sliced sides and also just by themselves.
I've also placed a baggie with serving of dry cereal as the grain side of a finger food lunch. Honey nut or plain cheerios-oatmeal squares etc. Lots of choices with dry cereals some better than others-some can double as dessert. Ha!
It's much harder to incorporate veggies in a cold lunch so when I can I'm creative by finding recipes online through others that sneak veggies into cookies and brownies and breads. Think corn-broccoli in cornbread and cucumberor spinach in brownies. If it's disguised it's more likely to be eaten and it STILL counts!!
To top off my kids lunches not all the time but often-especially during difficult times (when daddy is deployed and they're missing him more or perhaps they're concerned about a test or whatever) I include a short simple note a teacher can read to the kiddo or kid can read to self. Preschool age loves me to sketch a goofy picture or include a photo magazine cut out of whatever they'll enjoy. Sometimes my kids save these little things and I find them later in their backpacks or tucked away in their rooms. It's the TLC added to their lunches. :)
Sometimes there's a SACK LUNCH required for field trips in which all disposable things are required. In this instance I use the paper bags that you can buy in colors and I either draw pictures on it with colored markers and their name of course or I put stickers all over it to decorate it. Ziploc bags also come in an environmentally friendly variety now.
Regular ziploc bacs come with School box top square to cut off and keep for those schools that are doing that-and Capri Sun pouches are also recyclable for schools and earn up to 20 cents EACH towards new supplies. You can look that up online as well if interested. I know other moms read these even when they don't reply so I thought I'd just share all this info in one fell swoop.
HAPPY LUNCHES T.!