The M1917 Enfield left to me by a great uncle. Part nostalgia for him, but as a still well made and functioning gun in and of itself.
This little porcelain figurine of an elf given to me by a great aunt (wife of the uncle) when I was about 6 years old with her telling me that she always thought of me as her special elf.
My copy of Calculus (1st edition) by Michael Spivak that was the text for my honors Calculus class first year at university. Its binding is falling to pieces now, but I still enjoy reading chapters in it for the clear rigorous coverage of the subject as well as a lot of related side material.