George Martin's Song of Fire and Ice It is a bit more mature, but it is one of the defining series for contemporary fantasy
But now a list of all possibilities
1. Issac Asimov, I, Robot is probably a good place to start.
2. HG Wells, War of the Worlds
3. Bernard Cornwell, The Warlord Chronicles one of the best examples of Historical Fantasy. Also in my opinion one of the best King Arthur Stories out there
4. Michael Crichton, Jurassic Park
5. Christopher Paolini, Inheritance Cycle Now, hear me out on this one. It is by no means perfect, but for a younger audience, it is a good entry point into the classical Sword and Sorcery Fantasy Novel
6. George Orwell, 1984
7. Haruki Murakami, 1Q84 Alternate Reality, overall entertaining read.
8. Ray Bradbury, Fahrenheit 451 Distopian Future Fiction. One of the all time classics.
9. Frank Peretti, Ted Dekker House: The Only Way Out is In Unique fantasy horror novel. Easy read, maybe keep a way from the kiddies.
10. Kurt Vonnegut, Slaughterhouse-Five
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Some others
1. Gregory Maguire, Wicked, Revisionist story of the Wizard of Oz
2. Andrzej Sapkowski, The Last Wish, Adult Oriented Sword and Sorcery Fantasy novel. The Witcher series provides the base for the game series of the same name.
3. Timothy Zahn, The Thrawn Trilogy , quite possibly the best Star Wars EU material out there. Well written, entertaining, if you like Star Wars, this series is a must.