dudl is a collection of tools to grab, encode, and rename MP3 files, archive them, and maintain a database of all files. On top of this runs the dudld Jukebox daemon that plays your files through gstreamer. dudld's strengths are the powerful tag based filters, the capability to cope with very large collections, and the network protocol to control its operation. There is a full featured command-line client, a minimalistic GTK client, and a lirc client. Writing new clients should be easy with the supplied client libraries.
ripx is a script designed to make ripping CDs as easy as possible. It features CDDB lookup, ID3 tag editing prior to ripping, playlist file generation, album directory creation, and generally a nicer interface than many similar tools. By default, ripx uses cdparanoia to extract audio from CDs and lame to encode the audio to MP3 format at the quality of your choice. If you wish to use alternative applications for extraction or encoding, modifying ripx to handle these should be fairly painless.
mp3Rip is yet another MP3 ripper. This one requires very little user intervention--you just have to insert the CD and start the program. It rips the songs as quickly as possible so another CD can be started while other CDs are being compressed. It also organizes MP3s using CDDB information, and it can recover from errors with minimal wasted effort.