Yes, yes - I leave my itunes on almost all the time (except during thunderstorms or when I go on a trip).
It is a sort of illness (obsessive compulsive type thing) and certainly nothing to be impressed with.
However - when I saw that I was approaching the 300,000 track landmark I began turning off my itunes when I wasn't around because I wanted to see what track would be 300,000.
Well, it was Nosferatu Man by Slint. I was happy about that - I had just returned from a run and had played and repeated this song a couple of times, and was scrobbling the songs from my ipod (from the past week) when it landed in the coveted spot.
Nosfretau Man is a great song with a symmetric structure like a snowflake that really makes sense during a run when the brain is soaking in whatever chemicals the brain makes during a run.
Other songs that are great during a long run:
It's A Fast Driving Rave Up With The Dandy Warhols by The Dandy Warhols