Careful w/ the usage of the headphones. Shure, Entymotics, Ultimate Ears (I have these) are great sounding headphones, but not for working out. If you work out, then you sweat. That sweat gets in your ears and you can guess the rest. My Ultimates are horrible for workouts. You don't want any type of passive noise cancellation partly because of this. Also, if you're working out and you can't hear background noise, it could be dangerous if you're running outside for example.
For workouts, I like the Sony Sony MDR-EX51LP, $20 on Amazon. They do have the rubber/sweat issue but for $20, you can consider them disposable. The Sony MDR-A35G S2 are nice too, I've used similar and they are more durable with sweat.
