Osprey Hornet 46

Osprey’s svelte 46-liter Hornet backpack is so light and compact that at first glance you might think it’s little more than a daypack best suited for casual meanderings. But the pack easily expands and stretches to transform into a smartly designed overnighter. Two elements make this a great weekender: First, the careful use of lightweight fabrics and materials keeps the weight at a pound and a half, and second, the judicious use of flexible mesh means you can fill the top loader with essential items and stuff the extras into the large, stretchy side and front pockets ($159; www.ospreypacks.com).