Welcome to Engadget's back to school guide! The end of summer vacation isn't nearly as much fun as the weeks that come before, but a chance to update your tech tools likely helps to ease the pain. Today, we're tapping away on our brand-new smartphones -- and you can head to the back to school hub to see the rest of the product guides as they're added throughout the month. Be sure to keep checking back -- at the end of August we'll be
