I used to always listen to music on my ipod when running. I thought listening to music would help make the time go by faster. However, after my first marathon last year I decided to start running without it in order to see if it made a difference.
I now rarely bring my ipod with me when I run. I find that I pay more attention to my body during the run (my pace, any pain etc.) when I am not listening to music. I also like being more aware of what is going on around me when I run. If I ever find that I need extra motivation to help make the time go by faster I find a new route to run.
The funny thing is that now that I run without my ipod I still often find myself with a song or two stuck in my head while I run. Tonight it was Brother by Pearl Jam and Dying Days by the Screaming Trees. I must have listened to them on my ipod during the bus ride to work this morning.