I'm also caught between buying the new iPhone, since it will be my first one.
I have an iPod touch that is 32gb (current gen) and it is sweet. This is better than my crapberry at almost everything (except emails). So I will be selling it and using that money towards the 64gb iPhone.
My main reason is that I prefer not to carry around 2 devices. I will if I have to, for music purposes, but I want my next smartphone to be a touch screen and having two touch screen devices at the same time can screen "steal me" or "I am a giant douche bag".
My main concerns are push emails and battery life. I will absolutely need push email since I will be working in real estate. Second is the fact that I need great battery life.
I do wish the iPhone has a bigger screen, but the pros outweigh the cons.
I am with Sprint, so I have to see if they change their rates because I will be getting the Everything Plan.