I have to have music during my runs. I tend to want to run faster than I should at first. So I use music to keep my pace. I have 2 playlists of 150bpm (for a 10 minute mile) music ranging from pop to rock to punk and back again. The thing they all have in common is a good steady beat so I know to not run faster than that beat. I'm hoping once I get to a 5k and feel comfortable I may start not running with music but that'll be some time off.