I usually bring mine along - but it's more there in case of emergency - or to take pictures when my camera's battery dies or the card gets full. I don't even turn the thing on unless I'm off the bike.
As for tunes, I have a helmet wired for sound. It's old fashioned wire tech (Chatterbox intercom with plug-ins for phone and music player of choice). I found listening to music while riding a distraction in the twisties for me. I'd only use it if I was doing a freeway drone, so I don't use it anymore. Might have something to do with my abilty to walk and chew gum at the same time, but only if the two are synchronized.