Love my iPhone. I went to get a Blackberry actually, but the iPhone was way cheaper & offered way more. I was already with AT&T, so that's wasn't a problem for me.
I use it way more than I've ever used any other phone. I can check my five email accounts from anywhere and I love the social media apps. These things help me run my business when I'm out of my office. I also like a lot of other apps and a few word games.
My costs are similar to Jilly's, except I have unlimited text for only $5 a month.
I think if you just want a phone, there are cheaper options that would work fine. If you want a mini computer, iPhone is "da bomb".