Ars Technica is running a lovely story on the rise and subsequent fall of Winamp in the wake of news that AOL (who own Nullsoft) are pulling the plug past 20th December this year. This is truly a sad day given the rich history that Winamp has had and that it is on its last legs.
Hand in hand with Gnutella and other peer to peer sites around the turn of the millennium, Winamp was one of the more widespread .mp3 players that most in the fledgeling music downloading scene would use. East to use, skin-able, built in codecs for loads of audio and video formats, great plugin support, Shoutcast Internet radio, sweet visualisers (Geiss was my favourite), media library functions and more, Winamp was very much a media Swiss army knife for the masses while its competition floundered. Real Player was only truly good for its own streaming formats and DivX had plugins for Winamp that rendered its own program useless. Let's not even mention Windows Media Player, with its clunky interface, dreadful codec support and media licencing setup for anything you played on it.
For me, the one thing that killed Winamp was iTunes. Suddenly, the iPod was everywhere and needed iTunes to run, so people migrated over to it. Sure, you can get third-party support for iPods on Winamp, but people want something that just works without messing around. Nullsoft's purchase by AOL and subsequent firing of its founder Justin Frankel (founder of the Reaper DAW) probably didn't help, but then again, I don't think AOL really knew what they were doing with Winamp either.
Nowadays, VideoLan Client (VLC) has taken over the role of Winamp, with an emphasis on functionality and compatibility rather than interface tweaks. Foobar2K also deserves a mention if you are looking for a simple and elegant .mp3 player for low-power netbooks. Ultimately I haven't been back to Winamp in years but it still holds a place in my heart as my first .mp3 player in the early days of file sharing.