@khm @cienmilojos Seconding this.

I love Plan9 for note-taking, programming, music playback, etc. I use it to store recipes, todo lists, my digital 'notebook' (experiment logs for e.g. cooking, electronics projects, strategy games, run times and speeds); I use it to listen to CDs on the train, watch the occasional youtube video, go over my emails, read some comics (e.g. SMBC, questionable content), ...

just because it's not quite a traditional desktop doesn't stop it from being a general-purpose computing OS :P