My walk around headphones right now is a pair of Sennheiser HD 25 1 II. They are rugged, comfortable and sounds really nice. I used to favor in-ear headphones, but got tired of constantly having to remove and insert them, something not easily done. But now Sennheiser has released a new set of headphones that really tickles my fancy, the Sennheiser MOMENTUM, with a model matched for use with iPhone. There’s a forum thread on Head-Fi about them. With only 18 ? impedance and designed to work with smart phones, they should be easily driven to insane sound levels. Something I miss with the HD 25 1 II which really needs an amplifier to really shine, with 70 ? impedance. And let’s face it, it gets tedious to carry around a headphone amplifier with your phone and needing to unplug to answer.