Anybody have any experience with xTunes?  It's a free, open source, "comprehensive digital music system. It supports ripping CDs, burning CDs, playing MP3s, and organizing digital music in a library with playlists." [via Freshmeat]

The Library_Geek points us to a 3D XML Navigator and says "Try to imagine something like this applied to an OPAC. It certainly isn't perfect, but imagine the possibilities." I would add one more layer to this thought that it could be an excellent way to search an OPAC, reference databases, and librarian-selected index of Web resources simultaneously.