If Firefox and iTunes hooked up, their hatchling could very well be Songbird. Basic usage bugs have gone the way of last season's molting, so this fun app that's part music player, part Web browser, and all about music discovery, management, and playback is ready for every day use.
During installation, it'll ask if you want to load your iTunes music directory or another media directory, or perform the task later. Processing 5,000 songs took about 3 minutes, which is not a bad pace. It then asks you which of the preinstalled Songbird extensions you want to load. Most of these, like the iPod, Mass Storage Class, and USB device managers only make the app stronger.
The left sidebar provides quick links to bookmarks, downloads, your music library in an iTunes-style interface, and several music discovery Web sites to get you started. When you're looking at any Web site with MP3s available for download, Songbird will open a new window at the bottom of the main browsing pane. Double-click on a song to play it, and links on the right let you purchase the track from Amazon, iTunes, eMusic, and Amie St. They also tell you the format of the track--MP3 or AAC, for example--and provide a blog link for more info.
Songbird has a growing library of extensions, and support is slowly growing for those written originally for Firefox. Songbird is more than stable enough to take flight for the music-loving, Web-surfing fanatic in all of us.