I have this tune stuck in my head. It's the British Airways theme song. The one they play when they show their silly-looking air safety video.
It's the refrain from the song Viens, Mallika... (or The Flower Duet) from the opera Lakmé by Léo Delibes.
As songs stuck in heads go, this one is not bad at all. I still remember when The Call of the Ktulu used to get stuck in there for weeks. *shudder*