Earlier this week Apple announced it had sold a staggering 6.9 million iPhones in Q3 2008, beating RIM’s 6.1 million BlackBerry sales and crowning Apple as one of the top three mobile vendors worldwide. And thanks to the company’s “Think Different” bookkeeping, their $4.6 billion profit for the quarter isn’t just gross handset sales, but a mere portion of a typical AT&T 24-month contract.

With every other handset manufacturer rushing to market with a touchscreen mobile of their own you cannot deny that Apple has hit an out-of-the-park home run with the iPhone 3G.

So why am I not using one?

Even though I’m a Mac user of thirteen years I’ve also eight years of smartphone experience under my belt, going back to the infamous VisorPhone, in fact. And for me there are still four major ways in which Apple’s monster handheld comes up short:

1. The Keypad – With a growing number of iPhones around me I’ve had lots of opportunities to play with the virtual keypad. It’s definitely quicker and more intuitive than using T9 — particularly with one hand — but still can’t match the speed of a physical QWERTY. And I know a thing or two about physical QWERTY keypads.

2. The Contracts – I remain fundamentally opposed to carrier contracts for GSM-based devices. And while Apple has certainly revolutionized the mobile handset interface, its dealings with telcos worldwide have been anything but. I’ll let this excellent IntoMobile editorial explain.

3. The Camera – How can you possibly argue that a 2 megapixel fixed-focus camera with no flash or video is better than a 5 (or even 8!) megapixel auto-focus camera with both?

4. The Killer App – I’ve been combing through the iTunes App Store since it became available in Canada and I’ve yet to see that one program that makes the iPhone a must-have device. With all the smart developers out there embracing the platform I’ve a strong feeling that it’s on the way, but from what I’ve seen the iPhone’s killer app is still iTunes, as it has been since day one.

If anyone out there has a killer app for the iPhone, by all means let me know!