So Voldemort is a... (HP 6 Spoilers!)

[Tharen the Damned]

...Lich that has no less than 7 Phylacteries!
Why? because he can not be destroyed without all his Phylacteries (or Horcruxes) are also destroyed.
This is a great Idea by Mrs. Rowling. Imagine the Players, having destroyed the obvious Phylactery but facing the Lich again....

 

[Zweihänder]

SIX!!!!!! HE HAS SIX PHYLACTERIES!!!

His soul was split into seven pieces, yes, but one of the pieces stayed in his body.

It was kind of funny; immediately after reading HP:HBP I checked out the new Forgotten Realms book Champions of Ruin, and it had a relevant spell in it: Aumvor's Fragmented Phylactery.

 

[The Grumpy Celt]

...Aumvor's Fragmented Phylactery.

What does this spell do?

 

[Frostmarrow]

What does this spell do?

It fragments your phylactery Aumvor-style!

*ka-pish*

Thank's, I'll be here all week. Try the veal.

 

[Zweihänder]

It lets you break your phylactery into several pieces. All of them have to be destroyed before you can be killed permanently. Not strictly the same thing, but with the same outcome.

 

[Fast Learner]

But... Harry is one of his phylacteries!

 

[Rotogar]

But... Harry is one of his phylacteries!

My thoughts exactly!