Nokia's 5310 Expressmusic is 9.9 mm (0.38976378 inches, according to Google).
It's also got FM radio, Bluetooth (Bluetooth syncing compatible with Vista as well), and a multimedia player. Ok, the screen is not that big, but it's also got a 3.5 mm headphones jack, so you don't have to use any kind of adapter for it, and they provide a headset as well. The cool thing about the headset is that the microphone can be detached, and you can use any headphone you like, while being able to use your own headphones as a headset since the microphone is still connected.
Nokia usually has good reception, and good quality.
(C)