Headphones

That inline amp has some nice features, but I'm still hung up on the frequency response (20 - 20K). You'd still be missing some of the lower end and a bit of the higher end with that. I'd check the specks on your sound card and see what frequency range it can put out, and then base my decision on that.

For example, the headphone port on my powerbook is 20 - 20K, so the headphones your looking at wouldn't work at their full potential, compare that to my pioneer stereo amp of 10 - 50K, and the headphones wouldn't be enough.

Another thing to keep in mind is if you are listening to mp3s, the sampling rate will determine the quality of the recording, and the better your playback equipment, the better your chances of hearing the imperfections in the sound.

It really depends on how much of an audiophile you are.