I do think the family plans end up to be the best deals for U.S. folks. Benefits increase with the number of lines and if you don't use that many minutes (i.e. M2M).
We have four iPhone lines sharing 700 minutes, unlimited text. Each line is $58/mo after taxes, etc. for me in PA. I have the 200 bonus minute code on my line so we really are sharing 900 minutes.
Sometimes I envy the iPhone plans from Canada and the UK since you can get a plan with very few voice minutes, some number of texts between 200 and 1500, and not a lot of data for a very reasonable cost. I leave my 3G phone on data rather than WiFi all the time but could easily change habits and not hit 500MB in a month.
Heck, my wife is lucky to use 30 minutes in a month, but she pays the same as the rest of us (family plan or otherwise). She could carry around her shiny pretty iPhone and use it at her current levels and pay $30 a month for it in other countries.