I believe that with time, Apple will increase their offerings in this space, much as TiVo has with its WishList. Some day, I'll be tracking actors and film-makers much as I do bands today.
That's the idea behind my most recent contribution to The Apple Blog, titled Apple Adds “My Alerts” to iTunes Store. Per agreement with them, I will not be cross-posting the piece, but instead, have provided a link. Enjoy.