Audio library / catalog software

What do people use for organizing audio files? I’ve just been using directories and file names, but that doesn’t scale terribly well.

TheBrain is neat. It is ordering information in a directed graph where everything can be categorized under more than one order hierarchy. I like this a lot for collecting and linking up idea scetches.

It’s pretty expensive though, particularly if you just want to use it for organizing audio files. There is a free, but more limited version, but it might already be sufficient? (Have not used the free version for a long time)