Star Wars 4, 5, and 6 (1, 2, and 3 are more modern but also way more dorky.)
The Lord of the Rings movies (Only watch the Hobbit movies if you liked the first 3 movies.)
Alien (The sequel Aliens is also a great one, but it feels a bit different than the first one.)
Predator
Star Trek (The new ones.)
Stargate: Atlantis (TV show but it's one of the best live action Sci-Fi TV show I've seen.)
Thor 1 and 2
Captain Amercia (The 2nd one is going to be released later this year.)
Tangled (It was made before Frozen but Tangled is a great movie nonetheless.)
Pulp Fiction
Kill Bill Vol. 1 and 2
Total Recall (Orginial version, the remake was terrible.)
Man of Steel
Starship Troopers (It may seem dorky at parts, but they get to kill giant bugs, nuff said.)
The Arrival
Fire in the Sky