Here's a good thought to ponder on. The next iPhone, won't be called the iPhone 5. There won't be numbers anymore, because it doesn't make sense. Let's look at all the models they've launched so far.

The original, 2G iPhone was just called The iPhone.
The second iPhone was the iPhone 3G.
The third iPhone was the iPhone 3GS.
The fourth iPhone was the iPhone 4, which made sense from a marketing perspective because we were all used to the "3" from 3GS in the predecessor. And it was literally the fourth iPhone.
The fifth iPhone is the current model, the iPhone 4S—you're already using an iPhone 5.

Which means, the next iPhone won't be called just that. What do you think it's going to be called? Could it get the same treatment the new iPad got? The new iPhone?

iPhone 5 render by Martin Hajek