Headphones for quality, but quality earbuds for exercise scenarios. If you're doing cardio or even weightlifting, the sweat might be too much for headphones pads (velour, leather, etc). With noise-cancelling earbuds sweat is less of an issue and you won't feel as gross.
Headphones are cool for listening to your music in your car if it's an old model and doesn't have media input. Simply place your headphones above your ears and turn the volume up a bit more than usual. You'll feel those sweet vibes and still be able to hear traffic around you. But if you get hurt or killed I'm not liable hehe