iTunes is an Audio Player from Apple. I am a new user to this program, but I like it for more than its iPod-like trendyness.
This program is ideal for for those who have a large collection of music files. Almost all popular formats are compatible with this program.
Using the ID3 tags that are part of MP3 files, iTunes can organize your files in various ways including by genre, arist, time period, composer by or dozens of other variables used for categorization.
The program itself can search through your library of music, create and save playlists and even look up information on particular music, allowing you to read from their CD store library where you can purchase more music online.
iTunes has a few more features that are perfect in audio players these days, like an easy burn to CD feature, visualizations and ability to add an image to each song, like a CD cover or photograph of the artist.