My thoughts on the iPhone
1) I wonder how well the multi-touch screen will work when using the device as a phone. When I want to send an SMS while doing something else, I can pretty much feel the keys with my fingers and type without fully looking at my phone. The sames goes for dialing a number. I can open my phone and call people on my speed dial or even enter a number without giving the phone a lot of visual attention. I just don't think it'll be possible with the iPhone as there is no touch feedback.
2) I hate voice mails. I hate navigating a long list of menus, I hate the blinking red light, I hate being forced to write down or remember a phone number quickly, I hate how people don't repeat numbers or how they don't even try to speak clearly, I hate how I sometimes have to leave a voice mail for someone else regurgitating info from a voice mail I received instead of being able to just forward the email, and after using Gmail for so long I hate how I cannot search my voicemails. Last year, contacted the IT department at my work and canceled my voice mail!! The voice mail UI on the iPhone is much better than most cell phones. But it can still do a lot better.
3) I think that voice recognition is key for doing search on a phone. All of us have called 411 while driving to get directions, find an address, etc. I guess I can still call 411 on my iPhone. But that's a pity given that I'm holding a $600 device. I wish simple searches could be done completely using voice.
4) The price and the size of the device can be better. But I'm sure that'll take care of itself in future iterations.
Nice job to Apple for building this and for keeping it a secret for so long. At work, I sometimes hear the expression: "maintain a healthy disregard for the impossible". I think the Apple team on this project certainly did that.