I was thinking recently about the ankh that was in Hurley's guitar case, and what a letdown it was for me. I mean, the audience had been left wondering for a long time what was in the guitar case, and it was finally revealed to be...an ankh? Other than the letter that was inside of it, it wasn't relevatory at all - or at least it didn't seem to be.
The only other place I can remember seeing an ankh on the show is in the hand of the 4-toed statue. I wondered why an ankh was in the guitar case and what that had to with anything, and why it was important that it had to be broken open. I have also always wondered how or why the statue collapsed. These thoughts have led me to this theory: there is something in the ankh that is on the statue. And just like the ankh that was in the guitar case, it needs to be broken apart to get to whatever is inside. I believe that this is how the statue is destoyed. It is demolished to retrieve whatever is inside that ankh.