Nobody has mentioned:
- The Lord of the Rings. It is the secret gateway for us nerds to get into literature and poetry (do not skip the poems!). Read all the reference materials like The Silmarillion, The Hobbit, J.R.R.'s letters, the books his son Christopher edited and published, etc. If the poems seem weird or don't make sense, research why they are worded and structured the way they are.
- The Master and Margarita. Obscure and very unique. Make sure to get a good translation (if you don't know Russian) that has some annotations to explain the "inside" jokes/references