I bought divided "tupperwear" type containers at Walmart. I send his food in that and just put it in the daycare fridge when I get there. For drinks, we keep a gallon of his special lactose free milk at daycare and they wash the cups daily, so I don't have to worry about that. Our daycare actually provides meals, but with Nate's food allergies and dairy issues, it was decided that he should just bring his own, so we are the only ones. If everyone brought food, I guess we'd need a lunchbox to keep it cold...
Edit: I take an insulated one to school (work) with me I bought at Target. It's just a cheapy one that zips on the top. It's verticle too, but came with a compartment on the bottom that had a sandwhich container in it, so you can put things upright in that part. It's always worked well. I think it is ArticZone brand.