In reply to the sheep:
Must just be you and me then Sheep, I never run without music!
I dont tend to do any short runs and unless its in the wee small hours, I rarely run roads/pavements.
I find the change in tempo etc helps me cover the moorland, hills, bogs, tracks, peat hags etc etc far more easily. With Volume at "tooth filling rattle" I can blot everything else out of my brain other than the run.
Probably favourite running tune...She Sells Sanctuary The Cult? Following that the ipod contains what some might call a fine collection of Squeeze...Bon Jovi...INXS...The Cure....Elvis...Jonny Cash....Tears for Fears...White Stripes....Bowie....Kate Bush...etc etc....
Others might call it a load of mainly '80's tosh!