AKG's new K391 NC Active Noise-Canceling In-Ear Headphones with Microphone ($250) are exactly what the extended name suggests: these small, silver canalphones come with a noise-canceling module that lasts 35-40 hours on a charge, recharging a thin built-in battery via Mini-USB. Additionally, they're packed with two extra sets of rubber tips, an airplane adapter, and a travel bag. An in-line remote and mic allows for audio playback control and voice…
