I do:

    Secondary camera (with OpenCam) *oss

    Security camera (various software)

    Alarm clock with custom audio files (tibetan bells make a very unobtrusive wakeup sound)

    Guitar tuner & general audio                      recorder

    Mp3 player while working in harsh environments 

And it stays simless, in airplane mode, after a nice adb session where I uninstall just about everything I can. I could easily live without it, but I'm often glad to have it.