Steve Jobs has put the kybosh on rumours that Apple are considering a subscription service. He claims that the subscription model has failed so far because consumers want to own their music.
I disagree. Music is now a commodity and one of declining value, but people are listening to more of it than ever before. The subscription model is a natural fit for this type of behaviour and one of the main reasons it hasn't really taken off is the incompatibility with iPods. An Apple subscription service would change that.
Jobs likes to do things his way, but I think we'll see an iTunes subscription service before too long.