I use the "write them down" method, but admittedly I don't have that many to worry about. Maybe 30 or so. Fits on one side of a regular sheet of paper. And I use the same or fairly similar passwords for non critical stuff. A few of them have to be changed occasionally, after they've been scratched out and replaced once or twice, that's a good time to re-write the entire list and start with a fresh copy.