[I also stuck this on Facebook, but what the heck.]
For me, it's lentil soup. My mom actually makes great lentil soup, but she often made it when there was little else in the house to eat; we kids knew when she broke out the lentils, we were just about to that lone-olive-floating-in-a-jar-of-brine-in-the-back-of-the-fridge stage. For a long time I wouldn't eat lentils because I associated them with poverty.
What about you? What's your poverty food?