My favorite elementary school lunch (we were able to go home in those days – and I lived a block away) was a salami or oval-spiced ham sandwich and Campbell’s Chicken Noodle.   I’ve probably had thousands of cans over the years.
Now, we mostly do homemade soups – often in the crock pot – which we sometimes freeze.  Haven’t had much canned soup recently – but I guess if I had to pick one it would be Progresso’s Chickarina.   It was a quick bachelor meal in my apartment back in the day (with some buttered crackers).