I was reading a couple of the suggestions people had on the other board.  sorry I didn't post there but I'm at work and haven't had time to register over there yet.  
I think having the background volume change when another sound activates is possibly a bad idea.  If the background music changes volume everytime you select a game because it has a sound associated with it, it's gonna constantly fade in and out.  If you were to implement that, I would suggest a way to turn it off.  Just my $.02
-G