How can I turn off every volume but Media, GUARANTEED?

[summerfish]

AudioManager Widget: Once installed as widget on a home screen, each component of the Droid capable of making sound is shown. One tap opens the config screen, allowing speedy adjustments via a slidebar per sound component. Best way I've found to guarantee silence only precisely where ya want it. Runs smooth as silk (for months now).
AudioManager Widget for Android - AndroidZoom.com

Double that. You need this!

 

[crankerchick]

When the phone is on silent and you are streaming audio (didn't test with MP3s but it should be the same) you get a short silent blip that does intrrupt the song.

That's a good point, because the phone still send the tone, it's just muted. I change my recommendation to using Airplane mode AND silencing all volumes as recommended in my previous post.