Sewing related, I collect quilting books and magazines. I have years of magazines because you never know when you need that one particular pattern from 1998! In my defense, I DO go through them regularly.
Non-sewing related, I collect music boxes, moose and bear stuff and cookbooks...LOTS of cookbooks. I have some that were my grandmother's from the '30s and my mom's Betty Crocker cookbook she got when she got married in 1957 (and I've used it a lot!).