The Apple iPhone is the most wonderful frustrating device ever made. Well that might be strong, but Apple known for its design engineering hit this one out of the park. I can't think of another product that generated that much build-up and publicity. Plus they are maintaining it a year later.
Phone calls: Surprising the feature I am most satisfied with is the phone itself. As my Dad would say, "I just want a phone that can make a reliably make a call". All the other bells & whistles are meaningless if it is not a reliable cell phone. This is also the easiest phone to use for answering call waiting. You are offered clear choices of what function you want to perform when the call is received.
Voicemail: Once you get used to visual voicemail you'll be frustrated when retrieving a voicemail off of any other system. It's easy to see who or what number called you, the length of the v/m and to play it, call the number back, skip forward or back, and best of all select which message you want to listen to first.
iPod / MP3 player: This is a slightly watered down version of an iPod. You might be frustrated with some of the detailed features omitted, but it is a small price to pay to consolidated two devices. Many people have been frustrated by the headset jack. The jack is recessed; therefore use the Apple brand or buy an expensive adapter to use a standard 1/8" plug.
SMS Text messages: When the iPhone first came out this was a disappointment for many, but one of the firmware releases allowed messages to be sent to multiple parties at onetime. The SMS interface is more like a text message window you would have on a computer -- it shows the conversation history. The ability to send or receive pictures via SMS remains missing.
Clock: I know it seems weird to review the clock functionality of a cell phone, but this one's is outstanding. I can set up many different alarms with many options such as: alerts, frequency, and labels. The iPhone has replaced my alarm clock. The clock also has world clock, stop watch, and timer functions.
iTunes & YouTube: you can access both of these sites when you are connected via wifi. These are both light versions of the applications that you use on a computer. The biggest thing sacrificed is search capabilities. The parameters available to search are very limited.
Calculator: This is a basic four function calculator with memory. The interface is nice clean and simple. This is a calculator that is much more useful than other cellphone calculators because of accessibility. Unfortunately, there are several voids that are frustrating such as commas to help readability and scientific and other expanded math functions.
Camera / Photos: The built in camera is ok for snapshots, but not photography grade. What it lacks in camera quality it makes up with photo album presentation. You can sync your albums and can always have them at your fingertips. The interface is intuitive and like nothing on any other -- simply drag your finger to flip the page.
Internet: I chose to list this last as all of the media attention has been related to the phone's e-mail and browser functions. In my opinion these are satisfactory but could improve. When you're not on WiFi you will not like the Edge network unless the webpage is optimized for mobile content.
Other: I wish the phone could connect to a bluetooth stereo headset for listening to music. the bluetooth only permits telephone functions.
AT&T is currently the only domestic cell carrier for the iPhone. Cell networks are better in some areas & regions than others, so YMMV. Also, a little competition would be good for prices.
I have the 8Gb and wish it had more so I could download more video to my phone.
Conclusion: I know this phone is expensive, but I think it is worth the $400. The phone is about 90% of everything I would want; and that is what is frustrating! Why can't they do this one little more thing to make it perfect.
Wait until the 3G versions come out, then you can buy mine when I upgrade to the faster network. That will make both of us happy.