Let the hive mind of Engadget get that for you.
"I'm in the market for a new phone and money isn't a limitation. I'm also not partial to any particular US carrier, but here are some of the features I'd like to have: WiFi, GPS, good coverage in lots of places, push Gmail (a must!), physical keyboard (a must!), a touchscreen, decent battery life and a relatively slim body. And please, nothing that has a fruit logo on it. No offense to the fruit fans, though. Thanks!"
Which plan are you on? That seems like the unlimited text iPhone plan.
Being on the lowest voice plan possible (450 minute/5000NW/unlimited M2M) and the lowest priced iPhone data plan (200TXT), and adding random stuff, I keep my biil under 80$ after taxes.
In comparison, the cheapest o2 plan is about the same costs (do conversions and you'll see it is about $64/month before other items like taxes). They just get more texts and voice minutes than the comparable AT&T plan.