I just got a new plan in August. When I did my searching I went with AT&T because of where my "home" is, so that I can use it there.
AT&T is good for me
I also looked at VoiceStream which is now T-Mobile they had a really good deal going when I looked.
Also CenturyTel which is now AllTel was my old plan and At&T was offereing a better deal when I needed a new plan.
I would look at those three and decide from there who has a good offer going right now.
As a little shameless plug my mom is a CenturyTel employee
LOL They really are OK.