I second the DAC1 - it ain't tubed though - so no added warmth - but if you are going to hook it up to a jittery cable box then the DAC1 has a good reputation for handling jitter.
If you want to block out background noise or you do not want to disturb others then I love the Senn HD 25-1 II Pro - these are extremely dynamic and are magic with even a poor quality low power source like a portable player.
If you want to block out background noise or you do not want to disturb others then I love the Senn HD 25-1 II Pro - these are extremely dynamic and are magic with even a poor quality low power source like a portable player.