Neformal is a small audio player with a file manager and the ability to play file by file. It can keep bookmarks for favorite directories. It can compute RMS statistics for 16 bit PCM WAVs. Song lyrics are supported (via lyricwiki.org). Drag and drop can be used to interact with other applications. ID3v1 and ID3v2 tags are handled flexibly. The charset for tags can be selected. There is a built-in viewer for images and text files. The output device can be selected.
Arista is an easy-to-use multimedia transcoder for the GNOME desktop. It focuses on the goal of transcoding media, namely the devices you wish to play the media on. It is designed for use by people who are not familiar with audio and video encoding and want an easy way to get multimedia to their devices. It supports input from DVD and V4L devices as well as regular files.
Impulse is a bit of eye candy for your desktop. It is a widget that displays a graphical spectrum analyzer on your GNOME desktop. It is written in C and Python, and uses GTK and Cairo graphics to generate the animation. The impulse library creates a pulse audio connection context that reads the output stream from pulseaudio in a thread natively, which can then be read from Python. You can instruct impulse to either output the raw stream or output the FFT of the raw stream.