The grados simply offer incredibly accurate sound with clear highs and sufficient, but not overpowering, lows. The detail in sound is phenomenal. The listener will enjoy very subtle differences in tone color and dynamic level, and the sound always comes across naturally.
The SR-60s (and SR-80s) are perfect for portable listening devices, such as iPods, because the headphones present the best sound possible for players that lack an amplifier or a powerful driver. More expensive headphones with more power, detail, and precision are just wasted (and in some cases, don't even sounds as good) on portable devices.
Just a word of caution: Grado headphones are "open air." While this contributes to their fantastic sound, be aware that people sitting near you will hear your music. These may not be the best headphones for people on the go. Besides, they are not the most portable headphones anyway, although they do fold flat to fit nicely in a briefcase.
The bottom line: If you are an audiophile who primarily listens to your music on a portable device, these headphones, or perhaps the SR-80s, are the best on the market.
DIY Easy Pad Mod: If you feel uncomfortable wearing these phones for extended periods, go out and buy the yellow (yes yellow) Sennheiser HD414 pads. These plush babies fit right over you SR-60 driver casing, and increase the comfort dramatically for most. The also impact the sound, for the better. The highs sound "right." No sibilance, no shrill highs, just good sounding top end. The sound is slightly muffed but not as much as when the stock comfies are used. To futher the sound quality, perform the Quarter-mod as described above - the sound expands out more, correcting the flaw in the soundstage. The bass is less boomy, and the highs are sweet and well extended.