"MP3 players" are growing into "portable media players" -- with products like the Apple iPod nano growing larger screens for showing photos and playing video.
But what's the minimum you need for a basic MP3 music player? As the iPod shuffle has shown, you don't even need a display on a music player -- you can just shuffle randomly or play through a playlist. The minimum requirements for a simple MP3 player, then, are two controls -- one for volume, and one for next/back.
So here's an iconic design that satisfies these constraints, the iriver Mplayer -- a 1 GB music player in a tiny Mickey Mouse head.
It's ridiculously small and light -- 1.7 inches from ear to ear, and 0.6 ounces. And the Mplayer is trivial to use -- just twist one ear to adjust the volume, and the other ear to skip forward or back within or between tracks.
Just plug in to the headphone jack between the ears, and power up and transfer files using the mini-USB port on the bottom (it plays for about 9 hours on a charge). There's also a power button on the side, and a small light for status.
Unfortunately, while the Mplayer is a top seller in Korea, launch dates in the U.S. are still tentative.
See my Portable Media Players Gallery for details and comparisons.