I would save for a time capsule letters of defining moments such as weddings, birthdays, travel and such. Information about friends and relatives. Newspaper and magazine article. I just recently came across some letters and pictures of my mom's travels with her sister to Europe before she got married. It's like going back in time seeing stamped letters which can be also reflective of the time period. Also trying to read cursive, not print or even hand printed letters with terms and slang From the late 40’s and early 50’s. It's cool. The schools are not even teaching cursive hardly any more. With email, texting and such, you may have a hard time finding stuff to put in a capsule so you may want to print this information up otherwise it would be like a 78 rpm record. With technology moving as fast as it is, putting information on a cd or thumb drive may be like a floppy disk or a Zip drive in the distant future.