Kelli - I used to run with headsets on all of my training runs (not races, though), and one day I just decided to try a long run without it. I think I had become so dependent on music that it kept me from really focusing on my breathing, pace, etc., but I really dreaded those longer miles without music.
Ever since I left my MP3 player home that one day, I have yet to use them. It really makes such a huge difference, and I now have no desire to run with music. I didn't realize how meditative running could actually become and now I'm a little pi$$ed I waited so long to give it up! I still use it when I'm on the trainer as that is just mind-numbing, but never when I'm running. I love the silence now!