I read this crazy little post on myspace which I commented about in For the Record – random predictions about book 7, and that got me to thinking about the locket. If it is at Grimmauld Place, then Harry will have Slytherin’s locket, and if he inherits from Dumbledore, as everyone suggests, he will have Marvelo’s ring, and will have had or destroyed all the items Voldemort had as his heritage, Harry will have “inherited” Slytherin’s treasures.

Is part of what Voldemort accidentally gave to Harry the “magic” of being the heir of Slytherin? There is something in the balance of having 3 Voldemort items (diary, ring, locket) with destroyed Horcruxes on one side and horcruxes of the other 3 founder’s items on the other.