ADAM STRAUSS IS standing in his New York City apartment, holding the limp cord of his headphones, trying to choose between the two MP3 players on his desk: the iPod and the iRiver, its Korean counterpart. He cues up the same song on each, toggling the silver plug of his headphones back and forth like a 1930s switchboard operator.

He tries different songs, different genres, different instruments. The iRiver tends to sound better overall, but the iPod offers a little more nuance in the midrange. The iPod has a better battery life, but the iRiver still lasts eight hours—­longer than he’s ever continuously listened to music. Then again, he’s never owned an MP3 player. Is eight hours enough?

He goes back and forth, back and forth, testing vocal ranges, button resistance, interface aesthetics. His internal monolog races like ticker tape. Do aesthetics even matter? It’s going to be in my pocket most of the day. I’ve never seen a line out the door for the iRiver, but people line up at the Apple Store to get the iPod. Maybe those people know something I don’t. Or maybe those people are all chumps, paying a premium for an inferior device!

It would be one thing if it were just Adam’s decision of which MP3 player to buy. After all, it was 2003, the height of the personal audio device revolution, and Adam was a 29-­year-old audiophile. But it wasn’t just the iPod versus the iRiver. For Adam, it was also other decisions—­what shirt to wear to work, what to order for lunch, even what side of the street to walk down.