My husband and I will be visiting Philadelphia for the first time over Labor Day. We will have one night directly in the city, the Sunday before Labor Day. I would like some recommendations for what "not to miss." We will have one dinner and a couple of lunches. My husband and I are big foodies and will eat anything, as long as it's good. However, I will have my father, his girlfriend and possibly a child around 9 years old with us. I would like to stay in the cheap-moderate range (think under $20 an entree).
Also, any areas of the city that stand out above others for eating/staying would be appreciated.