The headphones that came with your portable music player probably aren't well suited for gym or outdoor use. Even if you bought a sporty model such as the Philips Nike MP3 Max, which comes with a sweet pair of clip-on 'phones, you may not be happy with what's in the bag. Like most remotes that come gratis with DVD players, on-the-house headphones are often less than inspired.

Though they may let you enjoy deep bass when you crank up an Usher song during your intervals, your full-size 'phones have no business at your local Bally Fitness. If their heft doesn't get you (and it will), some full-size models can be uncomfortably hot and make your ears sweat. And even though they don't eliminate noise entirely, noise-canceling headphones aren't smart to wear if you like to take your workouts outdoors. You could get clobbered by a Mack truck while obliviously rocking out to Naughty by Nature--or worse, while mindlessly humming along to Enya.

So what makes a good pair of workout headphones? They should be lightweight yet durable, comfortable yet firmly fitted. Cord length is an issue, too; if it's too long, you risk choking yourself on the Cybex machine, and if it's too short, your stride could suffer. Headband-style 'phones--which circle around the back of your head, under your chin, or over the top of your head--are pretty popular among the sporty set. They tend to stay put and out of the way. Earbud headphones are also a good choice, so long as you opt for models with a solid but comfortable fit; they're less likely to pop out of your ears, and if you sweat heavily, they're easy to keep clean. Of course, next to design and ergonomics, sound quality is the other determining factor when shopping for workout headphones. You don't need audiophile-worthy sound when you're in the gym, but you don't have to settle for tinny, weak, and lifeless-sounding music, either.

We rounded up a handful of headphones designed for active pursuits. Each has a slightly different fit and sound. Read the full reviews to find out which one is best for you.