Buying a player without knowing how much memory it has is like buying car without knowing how many people can fit inside. Memory can make or break an MP3 player. Generally, more memory is better, but it's more complicated than that. The most expensive part of flash memory players is the flash memory itself. So if you know that you're only going to use the player for half an hour at a time (if, for instance, that's how long your commute or workout lasts), 32MB is enough. However, we recommend looking for a flash memory player with at least 64MB of onboard memory and an expandability slot so that you can add more memory once the prices drop.

Flash memory is no longer the only medium for portable MP3 players. In fact, unless you need a very small, skip-free device, you're probably better off with a player that uses another form of memory, which will cost you less per megabyte of music. MP3 CD players leverage your CD burner and let you store the most music on the cheapest medium. And hard drive-based players contain the most music but generally cost more than the other options.

Finally, if you know you're not the type to sync up a player up to your computer frequently, stay away from flash memory MP3 players; otherwise you'll end up listening to the same tunes over and over again.

Connection
MP3 CD players are the only portable audio players that don't need to be connected to your computer in order to load songs onto memory. The basic rule of thumb is that if you have Windows 98 or above or a nonbeige Macintosh (beige Macs don't have USB), you should choose a player that uses the USB port, which will make those crucial file transfers faster. For the fastest possible file transfers to a hard drrive-based MP3 player, look for USB 2.0 or FireWire. Just be sure to buy the appropriate adapter card, because only new Macs currently come with FireWire installed as a standard component.

Sound quality
With a few notable exceptions, all of the players that we've reviewed have decent sound. Any aural limitations tend to have more to do with the inherent limitations of the MP3 codec rather than one player's rendering. Still, you should never buy an audio player with a signal-to-noise ratio of less than 85dB.

Software
Watch out for proprietary DRM software, which is usually found on devices from large, established corporations such as Sony, Panasonic, or Toshiba. These schemes can require the creation an encrypted copy of every song that you want to put on the player, making the companies' generally beautifully designed hardware ugly to use.