I'm well known for my annoying singing during working hours...well not just working hours. In fact I'll hum and sing quite constantly, especially if I've got a lot on my mind.
Often the selection of tunes turns mostly to game music. Theme Hospital tunes, Mario tunes, even Dizzy (from the spectrum) tunes feature highly in my repetoir (help me with spelling here!)
But another tune that keeps cropping up is the sailor song from Black And White - while most of the music is orchestral/synthy "big reveal" type tunes this was the most distinctive piece of sound from the game.
What a tuneful ditty!