Employing handle or shoulder strap, the Tour totes as a mild-mannered side satchel, easily stowing in overhead bins. But where planes and trains stop, this travel chameleon gets going. Deploy the cushy, adjustable hidden suspension and the Tour morphs into a legit 3,750-cubic-inch backpack primed for cruising inn to inn. A plastic panel stiffens the frame and protected my spine from bounce-induced bruising from a bottle of Johnnie Walker inside. For stripped-down day trips, simply unclip the removable 850-cube daypacksmartly rigged for a hydration reservoir and digital audio player. www.rei.com.
Bonus: A daisy chain and multiple lashing points give it the carrying capacity of a yak.
Bummer: The organizer panel's narrow opening means tough access for big paws.