I have AT&T and since they have merged with Cingular, my coverage area has doubled. I have a GSM plan and a phone that allows me to check email and surf, etc. I am happy and totally impressed w/ AT&T of late and wouldn't hesitate to recommend. I have NO roaming, period, with my national GSM plan.
My phone is way cool too. I send/receive a lot of text messages and my phone flips open to a hidden QWERTY keyboard, which makes texting a heck of a lot easier. I can't say enough good things about this phone. AT&T usually has a deal on it - free if you sign up for a term-contract. I'll even give you the link to the phone because I like it so much. Great signal, battery lasts a long time, few coverage issues.
Mine does not have a camera because where I work does not allow camera phones, but the upgraded model (Nokia 6820) does have a camera.
Feel free to PM me if you want - I've never been this impressed w/ a phone or a service provider before. I don't have a landline at all (and haven't for almost 2 years) and I've never had issues.