Oh, and Conrad’s “Heart of Darkness” became “Apocalypse Now.” (Though a lot more changed than just the title!)
You’re entirely correct. Soon after posting that, I realised it was wrong, but I couldn’t remember what the correct title was, and couldn’t find the book it was in, so I left it alone. THANK YOU. This would have bugged me.
(And I think Keith’s correct about Something Wicked This Way Comes. When we read the novel in school, it was Something Wicked This Way Comes. A phrase that shows up a LOT in the novel.)
It’s not a big change, but Charlie and the Chocolate Factory became Willie Wonka and the Chocolate Factory.
Part of Judges became Samson and Delilah, and most of Exodus became The Ten Commandments (yeah, I know, I’m pushing it!) 
Zev Steinhardt
Don’t forget: Beowulf became The Eaters of the Dead (book) became The Thirteenth Warrior (movie). Which I actually enjoyed (the movie and the original Beowulf). Don’t know that I enjoyed Crichton so much–I enjoyed the new viewpoint but didn’t think he added anything else. But I’m an English major, we’re supposed to be weird like that.
Snicks
Romeo & Juliet became West Side Story.
Ethilrist wrote:
Hell, if Broadway musicals count:
“The Wizard of Oz” became “The Wiz”.
“Little Orphan Annie” became “Annie”.
“Old Possum’s Book of Practical Cats” became “Cats”.
The later chapters of Genesis became “Joseph and the Amazing Technicolor Dreamcoat”.
The Gospels became “Godspell” and “Jesus Christ Superstar”.
“Auntie Mame” became “Mame”.
“Green Grow the Lilacs” became “Oklahoma!”.
“Tales of the South Pacific” became “South Pacific”.
“Liliom” became “Carousel”.
“Logan’s Run” had a “Carousel” in it, too. 
Pick, pick, pick.
Discord in Scarlet was the basis for Alien.
The New York Post article “Cop Gives Waitress $2 Million Tip” begat the movie, It Could Happen to You, undoubtedly the worst title change of all time.
The coolest of all book-to-movie title changes has to be when “Rocket Boys” (not technically a novel, though) had its title changed to “October Sky” for the movie. A perfect anagram of the original title!
Stanley Kubrick had been working on adapting Brian Aldiss’s short story “Supertoys Last All Day Long” for many years when he unexpectedly died. He had discussed the project off-and-on with Steven Spielberg, who decided to pick up the reins after Kubrick’s death. Spielberg is using Kubrick’s alternate title: A.I.
For what it’s worth, the movie comes out at the end of June. Here’s the official site, if you want to check it out.
“The Awakening” became The Grand Isle
Well, the situation is a bit more complex…Bradbury’s short story “The Black Ferris” came first, in 1948. Years later, he used the idea of “The Black Ferris” to create an outline for a movie idea and was encouraged to expand upon it so that a movie could be created. The novel Something Wicked This Way Comes was the result of that expansion. So, I’d still say that the movie came about as a result of, originally, the short story, and that the retitled novel was basically a script for the eventual movie.
There’s more information in Ray Bradbury’s introduction to the book, including this great quote:
[Moderator Hat ON]
How’d I miss this one? Moving to MPSIMS…
[Moderator Hat OFF]
actually, EL Club Dumas was first translated as The Club Dumas (how surprising), then made into the for-s**t movie The Ninth Gate, then republished under that title.
why oh why do books I love get turned into such AWFUL movies?!?!?! There will be HELL to pay if those Hollywood people mess up Good Omens or Neverwhere…
Re Good Omens, fear not; Terry Gilliam is doing it.
The Coen brothers took Dashiell Hammett’s The Glass Key and ran with it to make Miller’s Crossing. There are also two versions under the original title. The '42 one is really quite good. Haven’t seen the George Raft version yet.
Elmore Leonard’s Rum Punch became Jackie Brown.
If I had a dollar for every time Cyrano de Bergerac, Pygmalion, The Prince and the Pauper, or Romeo and Juliet was massacred and retitled, I’d buy you all a beer.
The short story “The Foghorn” (Ray Bradbury) became “The Beast from 20,000 Fathoms”.
Shakespeare’s “The Tempest” became “Forbidden Planet”.
The book “6 Days of the Condor” became “3 Days of the Condor”.
Here’s a couple of really grungy ones.
Bram Stoker’s Dracula was filmed as Bram Stoker’s Dracula. Likewise, Mary Shelley’s Frankenstein became Mary Shelley’s Frankenstein.
Bradbury’s “The Foghorn” is actually a bit more complicated. It was originally published, in The Saturday Evening Post, as “The Beast from 20,000 Fathoms.” It was retitled “The Foghorn” when it was reprinted in Bradbury’s collection Golden Apples of the Sun (I think), and that’s since become it’s “official” title. So does the movie Beast from 20,000 Fathoms count as a title change or not?
Wasn’t aware the story was published under that title in the Saturday Evening Post (though I was aware that it was published by them), thanks for the info.
Another for the list is “Leiningen versus the Ants”, which was filmed as “The Naked Jungle”.
Jules Verne’s “Captain Grant’s Children” (or was it “The Children of Captain Grant”?) became “In Search of the Castaways”.
This’n started as a British TV series, so it’s already been bungled by Hollywood - they never picked it up for air or video…