MetroPCS offers that, but only in their direct markets (they don't do roaming agreements). I was fine with them until I started having to travel to places they don't cover. Plus, they're CDMA and I didn't really like their handset selection. I want an Android phone :-} (maybe when LTE comes, which they've said will be their chosen direction, I'll think about going back).

Boost offers it, on a more nation-wide basis than MetroPCS ... but they've got an even WORSE selection of handsets, and they're mixed CDMA and IDEN. And... I think their unlimited service is on the IDEN network.

T-Mobile has unlimited voice for $50/mo ... if you've been with them for at least 2 years. That makes $85/mo total for unlimited voice, messaging, and data. But, again, you have to be on their loyalty program (unfortunately, I've been with them for less than a year).

Personally, as MetroPCS and Boost gain more momentum, I expect to see T-Mobile react in their pricing (since they're the smallest of the big 4). I think that, for nation wide coverage, $70-$80/mo is a reasonable price for unlimited everything. (and, note, Sprint is at $100/mo for that; and I pay $100/mo for it on T-Mobile, only because I'm on a family plan ... otherwise it'd be $125/mo)

Give it a year or three... I bet we'll see the little unlimited carriers (MetroPCS and Boost), and the big 4, meet somewhere in the middle. Which, again, I think is going to be around $75/mo.