We just got smartphones a few months ago. I like mine because I don't have to carry both a phone and an iPod to listen to audiobooks now. I also try to keep a Kindle book on it all the time because sometimes it's not appropriate of advisable to have your headphones on (in?). Having internet almost anywhere is nice and so is having navigation. But I would have a computer with an internet connection implanted in my head if I could.
That said, we wouldn't have made the switch if we hadn't found a cheap provider.