I have a similar deal to Manchops:
Virgin Mobile
$27/month prepaid is 300 voice anytime minutes, unlimited data, unlimited TXT and MMS
It's on the sprint network and coverage is fine in CO, NJ, NY, CA in my experience. The data is not fast by any means, but it works well enough to stream music continually while in the car, do GPS/maps navigation, check email, twitter, and the occasional clutch web page in a pinch.
I bought a cheap LG Optimus Android phone that I will use at least 2 years which amortizes to somewhere around $6-$9 per month (I forget exactly how much it cost).
I do any long calls on my computer over google chat, but for the most part I barely use voice calls.