I'm sure you'll find useful recent threads/questions+answers but I'll put it out there. What do you need your phone to do. I guess the iPhone available now or maybe even the old one would suit your needs. Apple's not the kind of company to make revolutionary changes to aesthetics or hardware, most of the time everyone is happy, the ones who had been waiting for a short while and the ones that bought one the day before. It's good business, IMO, it's what keeps people happy with Apple. In technology waiting is never good because most of the time you end up spending your time doing just that, waiting. There's always something better around the corner.
Let's get to the iPhones' case. The best case, announced in May or June and released in June/July, probably different back shell,matte black made of metal. Same prices, same displays, maybe 3.2MPx instead of 2.0. A higher priced 32GB.
Worst case scenario: September Release, everything the same, higher priced storage bumped.