Pen and paper to create a mind map while the meeting/lecture/session is going on. Also, I record meetings/lectures/sessions with my usb dicatphone.

When the meeting/lecture/session is over, I'll use a combination of my mind map, recording of the talk and several books to type up a decent document. Then create a better mind-map with more detail and keep document, mind-map and detailed mind-map together for future reference.