(Warning: if you're expecting something serious...)
So far, for the past three or four times I've started my iPod playing a random playlist, it's started with Depths of the Soul from the Final Fantasy XI: Chains of Promathia soundtrack. (And, in case you think that it may be some especially profound music, it's the dungeon party battle music - the music that plays in Chains of Promathia areas while you're in a party and in "Attack" mode.)
Not that I don't like Depths of the Soul, it's an interesting song - but I don't need to hear it every time I start up the iPod...