Patagonia MLC

Messenger bag meets backpack in the Patagonia MLC ($160). Designed to take up as much space as carry-on laws allow, the MLC can hold three to five day's worth of clothes, and converts easily from a briefcase-style bag into a backpack for frantic trips through terminals. An internal floating divider and water-resistant laundry locker let you keep your dirty duds away from the clean, while its coated fabrics provide protection for your goods in bad weather.