A week from now, Apple will be announcing its sales figures for the past three months on its quarterly earnings call. Analysts think the company sold in upwards of 12 million iPads and 33 million iPhones, thanks to the continuous momentum of the new 4S.

But according to Goldman Sachs’ Bill Shope, Apple’s next smartphone launch is the one to watch. The analyst recently raised his Apple stock price target from $700 to $750 on the belief that the sixth-generation iPhone launch is the most important one ever…

In a note to investors yesterday, Shope wrote: “The iPhone 5 launch is likely to be one of the most important smartphone product cycles we’ve seen to date.” And considering all of the expectations that Apple has to live up to, he might just be right.

First of all, the entire tech world thought that Apple’s last iPhone was going to receive a radical makeover. But all of the reports and third-party cases that supported that theory quickly faded from memory as Apple introduced the familiar-looking 4S.

Obviously, with the help of Siri, the holidays and other factors, the device still sold in record numbers. But if you think that Apple will be able to pull that off again — release another iPhone 4-like handset with a minor spec bump — you’re high.

Secondly, you have to realize that Apple has sold more iPhone 4S’ in the last 6 months than it has of any iPhone model ever before. In fact it’s sold more iPhones period. So it’s either going to have to convince a lot of other platform users — Android, BlackBerry, etc. — to switch to the iPhone, or a lot of current iPhone users to upgrade. And at this point, that’s a pretty tall order.

Mix in the fact that investors are already unsteady about Apple’s ability to keep up its ridiculous growth pace — its market cap is more than double what it was last year — and that piles on even more pressure for the company to deliver a hit.

Thus far, rumors regarding Apple’s next smartphone are fairly scattered. Some say it will have a 4-inch screen, others say it will be made of liquid metal. But if there’s one thing you can count on, it’s that it’s going to be impressive. Apple has a lot riding on it.