Of course, I pondered buying an iPhone when it enters the German market in November. But I decided that it won't improve my mobile productivity in a way that justifies the money spent. I agree that the iPhone has the most advanced user interface of all smartphones. But the lack of third party software is a killer. Even if it is true that Apple will release a software development kit in 2008, I'm convinced that they will control which applications will be made available over the iTunes store. I doubt that there will be an IM application while AT&T or T-Mobile want to sell SMS.
I've been using the Nokia E61 for many months now and I like how it's equipped with 3G, WiFi, a decent browser and a QWERTZ keyboard. That Nokia doesn't prevent me from installing new software enabled me to add applications for IM and RSS feed reading. Because I can do small things online without lugging around my MacBook Pro, I'm very happy with the phone.
Based on this experience, if I wanted to spend money on a new gadget (which curiously isn't the case, seems like I'm saturated ATM), I'd rather consider the Nokia N810 than the iPhone. It's a small tablet with a touch screen like the N770 and the N800. The screen of the N810 has been improved, though, and the device now also sports a slide-out keyboard for easier text input.
For more information, take a look over at Internet Table Talk.