MP3 players: the MP3 player continues its evolution from simple audio player to complex multimedia device.(Home Entertainment: Digital Dominates)(Buyers guide)

More and more players come with color displays and the ability to show digital photos transferred from your computer, sometimes while the music is playing. Such models usually also play music videos, TV shows, and short films.

As digital players morph, one thing remains constant: The brand name that's on most of them. Apple's iPod players still account for more than three out of four MP3 players sold. Hardware alone doesn't explain Apple's dominance. While iPods score well in our tests, so do players from other manufacturers, many of which offer capabilities and features that iPods lack.

Apple's success rests in part on its creation of a self-contained digital-entertainment system. iTunes, its content-management software, works seamlessly--only with iPods--a fact that's prompted the French government to sue Apple for monopolistic practices. Its online iTunes store offers by far the largest library of online video content, supplementing its dominance over online music sales. Its content includes many exclusives and also offers comprehensive one-stop access to podcasts, the booming (and mostly free) online downloads that offer everything from National Public Radio broadcasts to music-preview shows to weekly self-help recordings.

And while you can play content obtained from the store (and use iTunes software) on virtually any computer, including Windows PCs and Macs, you need an iPod to enjoy it portably.

Not that all innovative content comes from Apple. Other legal online content sources include BuyMusic, MSN, MusicMatch, Napster, Real, Sony, Wal-Mart, and Yahoo. Unlike iTunes, some of these sites also offer subscription-based services, typically for less than $10 per month, that let you listen to music on your computer in real time (streaming). Downloaded songs from contemporary artists typically cost less than $1 per song, or $10 for an entire album; music videos, hit TV-show episodes, and short films cost $2 each.

Free online music-sharing, still the most popular way for acquiring MP3 music, has been driven underground by a flurry of record-industry lawsuits and a 2005 U.S. Supreme Court ruling. (The justices unanimously ruled that the popular music-sharing site Grokster, as well as similar operations, could be held liable if their networks were used to illegally distribute copyrighted music.) Napster, a pioneer of free peer-to-peer music-sharing, now allows you to stream music free from its (now legal) site, for up to five listens per song.

Before you buy any digital player, be sure your computer can handle it. New computers shouldn't be a problem, but make sure any player you're considering is compatible with your older Windows or Macintosh computer (including its operating system). Keep in mind that some operating-system upgrades can exceed the price of a player. …