Lets take over the naming of the book. You never know, Jo might be inspired!

Harry Potter and:

the finding of the horcruxes. (naff).

the end of Voldemort. (hurray!)

the end of the world (eek!).

the horn of the quintaped (im not even sure if they have horns).

the lost cousin of Voldy. (lol).

I know these are pretty lame but i just thought i'd sick them i as an example. If I come up with anymore i'll post them. Don't forget to do the same!