10. Spider-Man 4
Granted, Spider-Man 3 wasn't exactly the greatest movie in the world (nor was it the worst, contrary to popular belief). Regardless of its quality, the third chapter in the Sam Raimi-directed trilogy of Spider-Man flicks brought an insane $890 million to the table; had Raimi and friends set out to render a fourth installment, it appears that the resulting picture - Spider-Man 4 - would have grossed a bunch of money.
And by bunch, well... you can probably assume that it would have been somewhere close to the billion mark (given the way that each new installment ended up taking more and more money with every entry), if not the full-blown sum. After all, Tim Burton's terrible adaptation of Alice in Wonderland film made over a billion dollars, which sort of gives hope to every other movie ever made, ever.
A lot of different ideas with regards to the plot for the film were thrown around, including one featuring Dr. Connors and his transformation into the lizard, though Sam Raimi and the studio failed to agree on what should happen. "It really was the most amicable and undramatic of breakups," he revealed with regards to its cancellation. "It was simply that we had a deadline and I couldn't get the story to work."