Labyrinths is THE best "idea book" I know, where the author has interesting, important ideas, and presents them both quickly and artistically. I confuse this book with Ficciones a lot, but that doesn't matter, as you should read them both.
I love Borges's essays as well. At least as far as ideas go, they're even better than the stories.
This is the monthly thread for posting media of various types that you've found that you enjoy. I find that exposure to LW ideas makes me less likely to enjoy some entertainment media that is otherwise quite popular, and finding media recommended by LWers is a good way to mitigate this. Post what you're reading, listening to, watching, and your opinion of it. Post recommendations to blogs. Post whatever media you feel like discussing! To see previous recommendations, check out the older threads.
Rules: