Same for me...except it was "Only in my Dreams" by Debbie Gibson. I was 12, so don't hold it against me. And most recently, I've listend to "Follow Through" by Gavin Degraw over and over again; for at least an hour or more.
I produce music/audio/video daily, and sometimes am stuck with a track or a sequence for a few weeks/80+ hrs
We did a whole 10 hour shift once, The Wreck of the Edmund Fitzgerald by Gordon Lightfoot!! not my idea!