I really want my grandmother's sewing machine; the one I learned how to sew on. I have bought one just like it, but I want HERS, specifically. It's not a rare or special machine beyond its sentimental value, but it was like an extension of my Gran's body for so many years and I miss her, so I want it to live with me. That's really my ultimate, must-have machine.
Fortunately it's still in the family, and has been earmarked to come to me when my aunt passes on.