I love getting mail from other countries. The things I like are the literature, film, and now I'm crazy about crafting and sewing. I also like the full moon and moonless nights. I love flowers, typography and seals.
I draw much attention oriental culture, especially the Japanese, and places that are the polar opposite of my country (Spain) and Australia, and countries in other hemispheres.
The postcards that I like are those that contain local artwork or other media, graphic design and original creations. I also like the natural place photos with original frames, but any postcard you send me will be fine.
Oh and I also love the typical food of other countries. If you include a recipe in your post, I love simple dishes that make you, desserts, etc ... :-)