The Bowers & Wilkins PX5 and PX7 might be the most beautiful noise-canceling headphones I’ve laid my eyes on. I know, I know, headphones should be about sound first and foremost, especially from a self-professed audiophile like me. And we’ll get to that. But more often these days, headphones are fashion accessories as much as they are audio products, so design merits some talking about.