I have found the following tools to be valuable on a sliding scale between useful and indispensible. Here they are with a brief description, grouped by command-line and GUI.
Terminal/Shell Based Apps
You can find most of these on sourceforge.
GUI Apps
History
Late in 2001 I decided to begin convert all my old analog music to digital format. I knew it would be a daunting task. I was wrong. It was an impossible task. With several hundred records and tapes, the process would take more time than I was willing to spend. The imperfect world of CD burning hardware, software, and media only made the job more challenging.
I eventualy found the right combination of media (Sony CD-R), Software (Toast 4), and hardware (SuperMac S900+Yamaha 8/12/24 SCSI CD-RW).
I concentrated on my rare or irreplaceable recordings and mentally shelved the rest. With a workflow in place that yielded consistently reliable results (CD's that would play anywhere), I counted it a success.
Unfortunately, the process still took too much of my time, especially adding in the time to print cover art. That along with the cost of the media, jewel cases (more than the media), and printed cover art (more than the other two combined) started wearing me down. This wasn't the solution I was hoping for. After all, I still had to find the CD, put it in a player, and so on. And to ensure I could find a disc I burned multiple copies (one for the house, one for the archive), which added even more time to the process. So I gradually lost interest, looking for something better to come along.
I wouldn't own an iPod for another three years, nor did I think I wanted one. What I really wanted was to play my music anywhere in my house without having to search for missing CD or wonder if it was actually a CD I owned or a cassette tape or vinyl album.
Even though iTunes is a great application, I didn't want to lock myself any proprietary system for music storage, retrieval, and playback. So I began where many projects do, googling for information to support the kernel of an idea. In this case, I was looking for an opensource solution to the storage, retrieval, and playback of digital music. Then along came NetJuke, and the rest is history. Within a couple of years, [Sonos] took the idea and packaged it for the consumer market.