It seems that once you buy a new iPhone you are pretty much stuck with your storage capacity for the next two years since the memory is not expandable and if you want to buy a different one, you will pay full price.

I spoke with people at the Apple Store, at VZW and at Apple on the phone and I am still left with the impression that I am making a blind guess in selecting anything other than the 64.

What is your personal guide on how to choose which model to buy?