Jamie, why don't you just try a pay as you go phone and see how much you use it?
If you find that enjoyable, then you could move to whatever you like. A full blown expensive iphone plan or whatever.
Before you get wringed into a two year commitment, you should see how much you use the phone and if you can even stand it.
Once you see if you enjoy it, or just tolerate it, and guage your usage, then maybe a plan for you and the wife would make sense?
I absolutely love my iphone, it's a ton of fun. My first phone I hated. Couldn't stand the ex calling me every ten minutes, and I felt like I had zero privacy. Reason I mentioned that is I have hit both extremes. I sure hope you don't.