Soldato
16GB is still a perfectly viable storage size for the iPhone. If you don't use it for music or video then it's fine. I have loads of apps on my 16GB 4S with space to spare.
For some people it is, and a lot of business users, yes.
But for the majority of general users i very much doubt it. Why would you want to carry an iPhone and an iPod or other media player around with you? One of the main points of these devices is that it's smart and can do everything you wish from a single device, a media player is up there with one of it's main functions.
For me, i should go for the 64GB version as i'm always going to be switching music in and out on 32GB. But hell am i paying that much for 32GB more storage.