Price: $249.95  

If you plan to spend a few months globe-trotting, the spacious Eagle Creek Thrive Pack carries what you need. The Thrives shoulder straps and hip-belt stow for easy plane and train travel, and for stuffing in lockers. Once you arrive at your destination, open the Thrives full front panel to get to the fresh underwear you stuck at the bottom. Leave the main pack at the hostel and take along the detachable daypack when you sightsee. The 19-liter daypack has pockets for passport, cell phone, and music player. When youre ready to move on, the Thrive has external pockets and lash points for securing your gear, just in case you picked up a few souvenirs, and 90 friggin liters is no longer enough. The included rain cover comes in handy while you wait in a downpour for your bus.