I'm a baker, and I baked for a living for years. I buy a big sack of AP flour and a 5lb bag of bread flour and use a combination when I make bread, heavy on the cheaper AP flour. You can make bread (obviously) with just AP, but it does actually work a little bit better with some bread flour or high gluten flour included, especially if you are using any wheat flour. Sure, it's nice to have a variety of specialty flours handy... I do miss working in a kitchen with pastry flours and a variety of textures of wheat flour and cornmeal- but in the real world you should use what you (and your budget) are comfortable with.