I used to swear by Winamp for playing my MP3s. For years and years I thought people were crazy for not using Winamp, then something happened with Winamp's development that had me looking for an alternative player. I flirted with the Quintessential Player for a while, and eventually ended up with iTunes.
Songbird is an open-source media player built on the same platform as my beloved Firefox. I've actually tried it twice before, when it was a proof of concept and Songbird 0.2. Now that they've released Songbird 1.0.0, I had to give it a third try.
It's so much better now. It's fast, stable and far more fun than iTunes. Like Firefox, there are add-ons that enhance the experience. For example, there is an add-on called mashTape that gives me band info, a discography, videos and more for each artists I play. I also use the side panel for song lyrics, and another add-on that tells me when an artist in my collection is coming to Toronto.
This is the open source iTunes killer I've been waiting for. It's finally ready for prime time.