Bowers & Wilkins C5 earbuds are the best for running in a limited sense: you won’t find better acoustics in a small package, but they’re worthwhile only if you’re good at taking care of your property and don't sweat much—they're a bit fragile and not waterproof. If you're hard on headphones and don't mind medium-quality sound, you might go with a more replaceable pair, like Skullcandy’s Fix ($40) or twist-locking, water-resistant Yurbuds (from $30). Still, I hate it when earbuds slip out when I'm on the trail, and B&W’s Secure Loop keeps the C5 in place on runs better than any headphone I've tested. The semi-rigid cord that comes out the top bends into a small, adjustable loop that wedges the earphone perfectly under the inner cartilage of your ear; that also keeps them from colliding with your sunglasses the way over-the-ear clips do. Additionally, they’re weighted with tungsten on the side closer to your noggin, further securing them in place. But there's just no getting around Bowers & Wilkins' sound quality—and yes, they sound that good. Just remember to pop them out and put them back in their case when you finish your run.