Gotta second the Grado recommendation. Grado sound is amazing. My "pocket audophile" setup is several tracks loaded onto the iPod with lossless compression and a set of Grado SR-125s.

Do note, however, that when -dsr- say "no isolation", he isn't kidding. The reason Grados sound as good as they do is the open design (which allows the diaphragm to move with little resistance.)

Not only do they not isolate, they project a bunch of sound. The would be a bad replacement for late-night SimCity activity.

The *nasty* thing about 'phones like the Grado or the Senn HD280s is that they're brutally honest -- and you'll find a number of tracks that you can't listen to, since you hear all the recording and encoding flaws. It is worse with poorly encoded mp3s and the like (one thing about AAC -- while it doesn't have the fidelity of a vbr mp3 or ogg that's properly encoded, it seems to be much more forgiving -- I've never had an AAC that was unlistenable.)