I use Cingular, they do a great job. My phone is almost two years old and still working great and I rarely have trouble with signal. THey are cheap if you are careful. I split 1000 minutes with my g/f and we never go over but we have free cingular to cingular talking and all our friends are with them.

Also they are really good about helping fix wet phones. I have dropped mine in the lake twice and both times just took it in, they dried it and gave me a free new battery and it all started working again. That is a good thing for us sailors!