I keep a daily brief diary and list of shore excursions, memorable meals and a full itinerary with flight numbers and flight equipment. I generally take photos of the airplane seats for future reference.
My father travelled with two 16mm movie cameras. When he got home, he would edit about a mile of film, add titles, a spoken commentary and appropriate music to his movies. It took him months to produce about a one hour movie. Unfortunately, we never got them transferred to video, so I fear they would be ruined if we tried now 40 years later. He would have loved today's technology. He also travelled with a portable typewriter and wrote the Daily Digest which has become a great source of information for our current day travels.