If you listen to music, just wear good earbuds that don't block ambient noise, and don't crank it too loud.
Stretching: By now most runners know not to static stretch from cold start, but not stretching at all is a bad idea. In my experience static stretching after the run works great, and so does dynamic stretching after a substantial (1mi) warmup. Also, most runners don't know how to stretch their upper body. In my experience it's really important to stretch your back.