I work for myself and I'm big into social networking, the iphone means I can do this on the run.
There are various apps that I can use to keep up with my business, evernote, facebook, twitterfon, linkedin. I don't need to cary an ipod round with me as I can load my tunes, video and podcasts via the iphone.
I have last.fm for random tunes and don't miss the radio.
My contacts list is detailed enough, and links the phone and sms well, and I have 4 email accounts that I can track and keep an eye on, so I never miss any queries or business.
I've a voice recorder for taking notes for back in the office, can use the map to get to a destination.
I have games on for when my kids are bored whilst I'm driving or can watch a film on the train.
I do miss a decent camera, but I can load a lot of pics of my kids for when I do the proud mummy bit and although I don't have the app I think there is one you can use as a video camera.
I had a viewty for two weeks (actually I need to sell it on) but quickly changed to the iphone once I realised how much I could use it for my business.
The battery lasts me a whole day but for saying I do so much on it I'm not complaining, my ipod never lasted much more than that on constant play! I just keep the usb leead in my bag and have a car charger to boost it now and again.