I use my iphone to listen to music when I'm running on the paved suburban trails I use frequently, but when I'm on real trails I use it only for GPS, especially if I'm with my friends or training partners.
I work in an environment a lot like the one Adam typifies in the video, lots of people all around me talking, banging away on keyboards, etc. And then my drive home from downtown Orlando out into the country where I live is full of traffic noise and commotion. I find myself overloaded after 2 or 3 days and I literally HAVE to go to the local trail systems on the weekend to get some balance back in my mind.
I just wish my local trail system looked like the one in the video. Imagine running from your front door and out into the mountains in 30 minutes? I listened to a podcast he was interviewed in over the weekend and he can summit his local high peak within an hour of leaving his house. Yeah, he's fast, but he's also quite fortunate (admittedly) to live where he doe. *jealous*