For a couple of years now, I have heard through the grapevine that Vejigantes in the South End is tasty and worth a try. We went and have nothing but great things to say. The food is fantastic and so are the prices! The staff is friendly (again, so important when eating out with kids!) and it's a colorful and cheerful place.
We went for lunch on a rainy day and had such a great time. We were the only ones in the place and decided to feast on appetizers so that we could try lots of different dishes.
The rice with beans was a hit with my kids as were the chicken empanadas. I went back shortly after with some friends and my daughter asked if I'd bring each of those dishes home so that she could have them in her lunch the next day. So there you have it, the food has officially been endorsed by a nine year old.