It'd probably look pretty weird if you brought a huge boom box on a plane with you as your carry-on luggage. But if you don't bring one on, how are you supposed to keep the entire flight entertained with your awesome mix tapes? The solution is the Boom Case, a big set of speakers built into a lovely old suitcase.
Boom Cases start at $250, with each featuring a 3.5mm jack for hooking up to your phone, iPod or whatever other music source you've got. It's got a built-in battery that can pump out over 7 hours of tunes, and a built-in charger for juicing it up. The only question is just how you're going to get it through airport security without them wanting to give you a full-body pat down.