For those who like changelogs, here’s an attempt:
* Support for Microsoft Windows (2000 and later).
* Support for GTK+ 3.0 (some plugins are not compatible yet).
* Support for SDL audio output.
* Multiple visualization and general plugins can be docked in the GTK interface.
* Configurable playlist columns with optional headers in the GTK interface.
* Control+F allows quick searching of playlist without opening a new window.
* New option to open files in a temporary playlist by default.
* New option to continue playing when the current song is deleted.
* The current song can now be queued to play a second time.
* New option to choose between 02:00 and 2:00 time format.
* Playlists can now be sorted by custom-formatted title.
* New command to refresh only selected playlist entries.
* Browser-like shortcuts (Control+T and Control+W) to add and remove playlists.
* Playlist autoscroll on song change is now optional.
* New buttons for shuffle and repeat in GTK interface.
* Playback toolbar better reflects current state (playing, paused, stopped).
* Prettier FFT visualizer and default album art in the GTK interface.
* Album art in separate files (e.g. folder.jpg) is now shown in the info area.
* Playlist and info area can now guess artist and title from file paths.
* Status bar format is more consistent across different file types.
* Cleaner and better organized song information window.
* The location bar in the add/open files window now works.
* Cleaner and better organized preferences window.
* New –verbose command line option to help with debugging.
* Transport and playlist plugins can now be disabled.
* Transport, playlist, and effect plugins are now loaded only when needed, reducing startup time.
* New Cairo-based spectrum visualization plugin.
* The status icon popup window can now be disabled.
* Closing Audacious can now be configured to minimize to the status icon instead.
* Desktop notifications now include artist, album, and album art.
* Additional format codes are available in song change plugin.
* Dynamic range compression works better on over-amplified tracks.
* A number of fixes to playback of Windows Media streams.
* A number of fixes to playback of cue sheets.
* iTunes cover art is now supported in M4A files.
* Seeking is now possible in raw AAC files.
* Additional formats (speex and shorten) are supported by ffaudio plugin.
* Many less compiler warnings with GCC 4.5 and 4.6.
We have also released 2.4.5, a maintenance update for the 2.4.x branch. It is not on the server yet but should be shortly.