Dave, a couple of problems with your math. First, any cell phone has a base (voice) charge, so we can cut $40 a month off right there. What you're paying for is the data plan, which you'd have to pay for any smart phone.
So really, it's not much different than a blackberry or any other phone with a data plan.
And if you share the plan, as my wife and I do, it's cheaper still.
By your math, my old freebie phone cost more than $1000, before you even get to additional text charges, fees to get pictures off the server (no other way to get them off that POS), etc. At least with the iphone, you pay your bill and go do what you want to do, without getting hit with extra charges every time you turn around.
And then when you factor in all it can do (and how many devices it can replace) the math starts to look pretty good.

