Personally I wouldn't want the two merged. I have an ancient iTunes account back when it was as username (circa 2005). When I got my iPhone 5 I was forced to set up a new iCloud account and also log in with the iTunes account. Since you can do both during activation, I'm not worried about it. I also let my boyfriend sync music from my iTunes account while he has his own iCloud account that he uses for apps. He doesn't care about buying music, so I don't worry about him spending a bunch of money. If my accounts were combined it would make our setup more complicated.