I'm reluctant to make book recommendations because I think what you read should have some connection to what you care about and what you've already read. In general, my recommendations are these:
First, I agree with what C.S. Lewis once said:* it's good to read old books. Old books and books written by people who are not like us have a remarkable power of helping us to see the world with fresh eyes.
Second, let your reading grow organically. If you liked a book you read, let it lead you to the next book you read. Often, books name their connections to other books. Or authors will name those connections, dependencies, and appreciations. The first time I read Lewis's Out of the Silent Planet, I missed the fact that the preface named H.G. Wells and that the afterword referred to Bernardus Silvestris. When I read it again as an adult, I caught those obvious references and let them lead me to other books.**
Third, I recommend learning the classics. That's an intentionally vague term, and I use it to mean that it's good to know those books that have given your culture its vocabulary. People who have stories in common have enriched possibilities for conversation. One of my favorite Star Trek episodes explored this idea, and it appealed to me because I believe that it's not far from how language really grows. If you need a place to start, check out one of the various lists of "great books" floating around out there. For instance this one, or this one.
With all that being said, if you're still interested in what I'm reading, here are some older titles I've enjoyed in the last year or so:
- Virginia Woolf, Mrs. Dalloway. (Mixed feelings about this one. My mind enjoyed it more than my aesthetic sense did, if that makes sense.)
- John Steinbeck, Cannery Row and Of Mice and Men. (I discovered Steinbeck late in life, thanks to a friend's recommendation. I've also recently read his Log From The Sea of Cortez and Travels With Charley In Search Of America. I think these two will forever shape me as a writer.)
- Graham Greene, Our Man In Havana, The Quiet American, The Honorary Consul, Travels With My Aunt, The Power And The Glory. (I will let the number of titles speak for itself.)
- Alan Paton, Cry, The Beloved Country. (I was surprised by how contemporary this old book felt, and by how relevant to America an African book could feel.)
- The Táin. Because I have a thing for reading really old books, and this is one of the oldest from Europe.
- China Miéville, Kraken. (London. Magical realism. Bizarre and witty.)
- J. Mark Bertrand, Back On Murder (I don't read many detective novels, but I really enjoy Bertrand's prose.)
- Cormac McCarthy, The Road. (The final lines spoke to my salvelinus fontinalis -loving heart.)
- David James Duncan, The River Why (I've re-read this one a few times. If you like trout and philosophy, you might like this book.)
- Mary Karr, Lit. (Third in a series of memoirs. Some of the best storytelling I've read in a long time. Brilliant insights into addiction, love, and prayer.)
* Lewis said this in his introduction to Athanasius' On The Incarnation (which, by the way, is now available from SVS Press in a dual-language edition, Greek on one page, English on the facing page.)
** There are two excellent books on Lewis' "Space Trilogy" or (as I think it should be called) "Ransom Trilogy": This one by Sanford Schwartz, and this one by David Downing.