Turns out there was an old thread about this topic (take a look at post #16 there ).

Whatever I carry, they have to be tasty enough so that I'd be anticipating the lunch time with eagerness . Haven't needed a cooler yet, but I think a cooler could be used as a trunk bag by itself.

I prefer to carry lunch in such a way that on my way home I would not need to carry empty boxes that take room...