I love my smartphone. 2 years ago I saw no need for Internet on my cellphone. Why would I possibly want to surf the web on a cellphone? Now I live on my phone. I do everything through it. I take it everywhere with me. If I don't have it with me I feel disconnected and vulnerable.
I love having my email with me wherever I go. I love being able to look up anything whenever I need to know something NOW. I love having Maps and never getting lost again. I love being able to IM my friends without needing to sit at a computer. I save a lot of money using internet-based apps and functions rather than making calls and sending expensive SMS'.
Unlike Grav80, my phone rarely ever gets used for calls, so it doesn't feel like it intrudes. And if I want to be disconnected, I turn all alerts off and leave it somewhere nearby. I would never leave home without my smartphone.