32gb should be the new minimum.
retina, HD photos and Videos eat a lot of space.
I have the 32gb and thankfully have a very small number of songs and my iP4 doesn't shoot 1080 but still i have to think about if i really want to shoot video or if i will just delete apps.
if they had 128gb i'd still not be able to import all songs and have space for apps. Apps are increasing in size and i have to weigh to download/buy an app or not because of the size.
and more memory will be better for the phone too. allowing space when updates are made. other smartphones may not have it yet but Apple can push those limits. you know if Android had 128 everyone would be saying Apple is behind the times.
the S3 is up to 96gb now... btw a 64gb mirco sd card is 70 bucks on amazon....