The eighth challenge in the 50 Day Music Challenge is 'most played song on iTunes'.
To be honest I didn't actually know this, I guessed it. I then went onto my computer, into iTunes to see if I was right. I was. By one.
My most played song on iTunes is 'Desperado' by Eagles.
I adore this song, obviously. It's beautiful.
If you haven't heard it, educate yourself and listen.