I could go on forever with this so I'm doing a list of 10 which came to mind first! One is from a TV show, with a LOT of death scenes but this one was the most surprising to people who were watching without reading the book first due to some excellent marketing.
- Alien - Chestbuster
- A Clockwork Orange - Ceramic Phallus
- Day of the Dead - Choke on 'em
- Fargo - Woodchipper
- Final Destination 3 - Rollercoaster
- Game of Thrones - Ned Stark - Betrayed and Beheaded
- A Nightmare on Elm Street - Tina's Death
- Suspiria - Hanging
- There Will Be Blood - Milkshake
- The Wicker Man - The Wicker Man