Features:

• It supports visualizations, DSP effect, and plug-ins ranging from MP3 convertors to PC games.
• It includes a spectrum analyzer, a graphic equalizer, a playlist, and a mini-browser for everyday Internet use.
• It offers MP3 to WAV conversion through the use of an output plug-in.
• It plays 18 different audio formats.
• It's completely skinnable. (You can find skins at Tucows Themes or Winamp.com.)
• It offers CDDB options and retrieval.

I've used WinAmp since its first discovery and I think that it has raised the bar for audio players.

Note: On the right hand side of the review, 3.0 WinAmp Alpha 666 Build#429 is available! It may be buggy, but this is definitely a great look at the upcoming release. I personally like the database manager idea.