I read The Big Sleep a few years ago during a foray into genre fiction I was making at the time. I liked it fine, but I can't say it left much of an impression on me. Sometime later, someone I follow on Twitter recommended (generally, not to me personally, in the context of like, essential noir novels or somesuch) The Long Goodbye, so I added it to my PaperbackSwap wishlist and a couple weeks ago it showed up in my mailbox. The timing was perfect: June was a busy travel month for me and engrossing, plot-driven books are about the only books I can manage to read when I travel. (This was also the reason behind my selection of The Death of Roger Ackroyd immediately before The Long Goodbye. I finished both books on planes.)
For a long stretch as I was reading The Long Goodbye, things felt slightly familiar, but I wasn't certain that I had seen the movie. Then, when I was finally sure I had, I found that the book diverged quite a bit from what I remembered happening in the movie. I looked into this after the fact, and it turns out it's not so much that my memory is faulty but that the movie is quite different from the book. Several characters are missing from the movie and most notably, the ending - which I remembered and was expecting - is totally different. The mood of the movie is also different. As the Wikipedia page explains, the movie was updated to be set in the present day (1970s), when a character like Philip Marlowe was anachronistic. Anyway, the differences meant the book felt almost totally new to me.
So, about the book: I loved it. The writing was incredible. This is the language that is both imitated and spoofed in detective stories everywhere. Reading The Long Goodbye, I felt like I was experiencing the real thing for the first time. It was beautiful, and funny, and evocative, and stunning. I couldn't get over it. Everything else about the book felt sort of incidental. The story was good, but not nearly so good as the telling. Good or bad, I found I could read right past and forgive the flaws and bits that made me uncomfortable. It was just such a pleasure to read.