Here is something to think about :
You know when everytime a player enters his/hers or friends' house that the music is all the same? Well, what if Kingsisle came up with a thing called "Jukes" , that can play different background music at their house. It could be available at each of the worlds' housing shops. For each world, there could be a couple different "Jukes" relating to that world. For example, battle music, commons music, golem tower music, etc. for Wizard City and so on. That might just be something to think about. I however thought about it as I was at my friends' Dragonspyre Residence and noticed Wizard City Music. The Jukes could either look like something you put in your house or you could equip it as if you would equip you house. Then when the wizard equips his/her Juke, they could teleport to their house and listen to it while they were doing their daily routines.
You think if I e-mailed that idea to KI they would like it? Who knows?