Apple has revealed its Fall 2010 iPod lineup at its recent media event, along with a new Apple TV, and a new version of iTunes—plus information on iOS versions 4.1 and 4.2. Here’s a quick summary of the key announcements, with a convenient gallery of photographs. Fourth-Generation iPod shuffle: Physical buttons return in this $49, 2GB screenless music player. Sixth-Generation iPod nano: The Click Wheel disappears, giving way to a touch-based…