Portable audio systems are great, but most aren't the kind of thing you want to be seen carrying around. Thankfully, that's not a problem with the TDK Sound Cube ($300). Packing 20 Watts of output power and two 5.25-inch coaxial drivers into a stylish box, the Sound Cube offers iCompatible USB, 3.5mm, and auxiliary inputs for connecting a variety of audio sources, and also let you jam along if you like by plugging in a guitar or mic. The only bummer? It's gonna need a standard power source, unless you like the idea of lugging the Cube and 12 D batteries around all day.