I would suggest you consider the sci fi and fantasy masterworks, The Iron Dragons Daughter, Replay, Fevre Dream, most recently The Demolished Man, before that Ubik, Three Stigmata of Palmer Eldritch but in the main I would recommend all of Philip K Dick's books Dr Bloodmoney, The Cosmic Puppets, Time Out of Joint (personal favourite) but I found Androids Dream of Electric Sheep disappointing (everything which is great about that movie is a product of the director and the actors) and Scanner Darkly I didnt read.
The Divine Invasion is a fantastic book if you like pseudo-spiritual reads, God returns from an exile on a hill in Mars, it explains brilliantly how he came to be exiled, how good and evil exist as opposing forces, why evil is inferior, also the victory over evil and how that comes about, a great book, although it is supposedly a trilogy with two other books Radio Free Albion and VALIS both of which are critically acclaimed but both of which I did not finish, could not finish, and I largely regard those books as the confused jottings which PKD made before the finally produced Divine Invasion.
Its a total and utter aside but I consider Divine Invasion as personal canon, along with Dante's Inferno and Milton's Paradise Lost and Paradise Regained, I have a personal canon of books which I consider are divinely inspired, whatever the official position on them may be and its unlikely to happen that they become even remotely recommended as they have so much trouble already establishing the canonical nature of the existing scriptures and saints and scholastics.
Replay I really liked but thought it was fanciful, I'd like its version of time travel and afterlife but its just imaginary, Fevre Dream has some of the best character development and portrait I've seen, the best literary example of evil I can conceive of, the Iron Dragons Daughter is some what disturbing but ingenius in its portrayal of fantasy and psychology, its also brilliant in its terrifying and wicked realism when it comes of all the creatures of fantasy lexicon, the true nature of elves for instance (or at least as Irish know them) is on display. There is a sequel, the Dragons of Babel, which is good but for fans I would say.
Broken Sword, Three Lions, are both great books by Frederick Pohl, I think, the guy took the poetic and legend weaving very seriously in Broken Sword but Three Lions is more just work of fun, entertainment, if you like Three Lions then a kind of sequel to it is Midsummers Tempest, its a kind of shakespearian fantasy, romanticism fights a final battle against modernity in civil war era england or maybe its earlier, not quite sure, its got Oberon and all the hoast of the supernatural wild hunt in it. I loved that book. It features Pan or Dionysus' Inn (not sure which) which anyone who is in mortal danger may access for one night only and party with all the travellers from the multiverse who have also found themselves in similar circumstances.
Finally, I would recommend The Drawing of The Dark, its idiosyncratic, but I feel I should recommend it as my favourite book, it features Finn Macool, Kind Arthur, some good writing on old swordplay and broadsword, an Irish character called Eammon Devlin, a battle between the west and eastern wizards which is behind the siege of Vienna by Ottoman Muslim forces, the "black" of the title is a magical stout which sounds a little like Guinness, the magicks of the west are bound up with craft beer. Some of the same mythos developed in this novel features heavily in Anubis Gates, although novel, considered the archetypical steampunk novel, if you like steampunk the only other one I would recommend is Morlock Night (though I think it is unfair to HG Wells).