AT&T, Cingular, T-Mobile (Score 5, Informative)

Those carries have been open for a long time: I've been using unlocked GSM phones on them for years. The iPhone is a big step backwards: it's carrier-locked and non-programmable. Far from moving the industry forward, Apple has been taking it backwards.

If you want a nice phone, get an unlocked Nokia N95-3; you get 3G speeds, a 5Mpixel camera, stereo speakers, GPS (works with Google maps), a Safari web browser, and lots more. You aren't locked into a contract or carrier, and you can put in a different SIM card when you travel.