The iPhone you want to buy, and the one you should upgrade to, isn't coming out until November.
The iPhone 8 and iPhone 8 Plus aren't that compelling, especially if you're coming from an iPhone 7 or iPhone 7 Plus. I'm stopping just short of calling them "just another iPhone," since I haven't seen them in person yet. The form factor looks almost identical and almost all of the exciting new features coming to the iPhone X aren't coming to those devices.
The iPhone X will have a brighter, more colorful and far more advanced OLED screen, for example, and a unique form factor that looks unlike any iPhone that came before it. It has advanced AI sensors in the new A11 chip that can help detect your face when you look at the phone (a demo of this failed on stage, but Apple has some time to work out the kinks).
People will see this iPhone and know that you have the new iPhone. I have a hard time believing anyone will say the same about the iPhone 8 and iPhone 8 Plus, save for the few who know Apple is using a glass back on both.
This isn't to say the iPhone 8 and iPhone 8 Plus are bad.
They're just not as exciting. They'll have features such as wireless charging, something earlier iPhones don't have, but almost everything else is an iterative step up from the iPhone 7 and iPhone 7 Plus. What's so exciting about that?
My recommendation: Try to stick it out for the iPhone X. It's the real leap in technology that you're looking for. It's the iPhone with the very latest inventions Apple managed to squeeze inside a phone, and it's the most exciting of the bunch.
You'll need to be patient, though. Pre-orders don't start until Oct. 27, and the phone won't begin shipping until Nov. 3. That's more than a full month after the iPhone 8 launches on Sept. 22.
I'd act fast, too, since rumors suggest the iPhone X is going to be in high demand and in short supply at launch.
Oh, and empty the piggy bank: The starting price is $999, as expected.