Why are ipods so good for listening to music?

A lot depends on what your purpose is for having music on. Many people like 24/7, wall-to-wall music but then become desensitized to it, no longer really listening, like having the TV on in the background. That's one danger of portable music. Another is that the ear is not really adapted to having the sound source in the ear canal, which is too close. So over time, especially at volume, hearing loss is to be expected.

If music is meaningful to you, not just another adornment or distraction, then it needs to be set apart somewhat from the hustle of everyday life and certainly not always in the ears. Further, the sound quality and musical quality ought to be considered. The iPod plays mp3s, which have reductions in fidelity to manage file size restrictions. Similarly, a car is a lousy listening environment since it's already quite noisy and the driver is already occupied with watching the road.

If your listening tastes run to teen pop and other pedestrian (and ephemeral) musical styles, the quality of sound and the setting probably don't matter because you're getting the equivalent of sugar water. (Heated disagreement on that point is expected.) If your listening tastes run to jazz or classical or other styles that are closer to art than commerce, then you will probably want live music, not recorded music.

Personal disclosure: I don't have an iPod or other portable music player and would never want one. I have a fairly high-end stereo system dedicated to music playback, not theater, but I don't have it on all the time. I actually sit and listen rather than have it accompanying something else.