Oh Boy, don't get me started! I am a bit of pack rat too, mostly photo albums from when I got my first camera in 1967 for Expo 67 in Montreal. I do have some Expo memorabilia as well, and a rain cape from the 76 Olympics in Montreal as well.
I also have a huge School Years scrapbook with all the reports, photos, artwork and certificates from each grade right through high school.
One of the strangest things I kept from childhood is a yellow plastic piggy bank. Don't know why, it's ugly, but I still have it!