23. Inglorious Basterds
Almost every scene is a standout, such as the suspenseful opening sequence and the underground bar. Each is carefully constructed to build to its climax, and the movie as a whole makes a similar journey. Though long, the movie holds your attention and makes you want to see it through.
18. The Truman Show
Released in 1998, this film was ahead of its time in examining how reality TV (and later social media and internet surveillance) could invade an average person's life. For example, it touches on how the "showrunner" attempts to control Truman by creating situations that he knows--based on data and analytics--will effectively manipulate his emotions.
12. The Prestige
Narrative ambiguity that leaves things (timeline, character motives, and even final outcomes) open to interpretation makes this movie a fun one to see for a second or third time.
4. Mulan
Another 1998 classic, Mulan is one of the last traditionally animated feature films from Disney. It tells a fresh story with themes that were uncommon in children's entertainment, such as war, duty, and honor. It's also different from other Disney films of its era in that the main characters are less talkative than other heroes.
2. Lord of the Rings: The Fellowship of the Ring
Though it's part of a larger epic, the film tells a complete story on its own. It's well paced, develops its cast of compelling characters and sees them grow as people, features intense action sequences and battle scenes, and ends with dual sadness and hope.
The rest of the list + rationale is at the source.