These two have built-in amps and magnets that help you stack them when they're not in use—and keep them from knocking around in your carry-on.
2. Music Balloon
Mic-like in appearance, this foam-covered wonder blasts music in all directions, and it's light enough to stow in a beach bag.
3. Altec-Lansing Orbit-M
With its rugged design (including a cord tucked safely into the device's shell), the orbit-M is ideal for trips that might involve hotel-room parties.