I easily fall into the trap of focusing on reading the newest books. I like recommending books, so reading new ones helps me do that. Unfortunately, it also means you are the fall guy for some pretty mediocre reading. Finding the gems in older books isn't always easy either. The Booker can be great, but you can't always rely on it. Gollancz in Britain publishes a series called Sci Fi Masterworks. The idea is that these are classics that should be promoted as prominently as the new stuff. From my experience, the selection is great. The books on page 4 are among the greatest of all SF books. The Masterworks editions are not easy to find in the US, but you can use the list as a reference at the bookstore or library.