Dictation on-the-go hardware
Olympus Voice Recorder WS-853 hand-held recorder with USB, uploads directly to computer.
Sennheiser ME 3 II Dynamic Microphone with cardioid capsule. Leaves the ears free, so legal to use while driving. Strongly directional, so you can use it in a noisy environment without it picking up a lot of background noise.
Both were recommended by Martin Shoemaker in the book On Being a Dictator: Using Dictation to Be a Better Writer coauthored with Kevin J. Anderson.