the phone is very important. spend the extra $$ to get a good one. ask the sales rep which one gets the best reception.
i ended up going with verizon and have been pretty happy with it. i also got the mororola startac phone. i have coverage at the green putin and takeout, and the nolichucky putin and takeout. it doesn't work in the park, or in some of pisgah.
verizon has several levels of coverage. i got the from anywhere to anywhere option with 400 minutes for $55
if you get the from the carolinas to the carolinas plan you can go all the way up to like 1200 minutes for $30.
i also know quite a few people who have been happy with suncom. don't know particulars, but all of this is on websites.