In northern cali ATT is the best choice, best coverage t-mobile and Verizon sucks here....
Sprint is the one with the bigger and better 3g for data network here, but for phone use its horrible.
Its a tossup, this is why I have a sprint air card, and an att phone, best of both worlds around here.
Now this in no way says I am happy with att price gouging its customers around here. $20 for unlimited texts? what!?!?! $30 for data !?!?! what?? 40 for only that little of minutes!!! ahhhrgghrr!
Edit: sad to say I have been with att for 11 years now (att wireless, cingular, att, att mobility, att)