I love maps, of course.
My middle child has a beautiful one that came with his collection of Lloyd Alexander books (His favorite books, btw). It folds out into a gorgeous poster-sized thing that looks like it ought to be framed (if you could somehow get the creases out).
My maps don’t look like that. They tend to be scribbles in the margins of notebook pages that barely give me a sense for rivers and mountain ranges–but they are incredibly useful.
Here’s the one I used for Anya’s simulation (see Leaving Hope).