Here a blogger organizes a pretty ass-kicking list of 1960s science fiction. Anyone who puts two PKD books on their short list probably knows what he's talking about, but don't merely skim the year-by-year titles, either. My own short list would probably include the anthology Dangerous Visions, the same PKD titles he chose, Dune, The High Crusade, and Flesh by PJF. Although, if you were to ask me the same question next year I'd probably provide completely different answers. I'm iffy like that.
there are other, less cheesy covers for this novel,
but this one is actually pretty accurate, right down to the horns
My own to-read list is kept on a Google document, which I can access with my phone's Google Drive app whenever I'm away. Most of the books on the list can be found in used bookstores and thrift shops for a dollar or less.