Happy 63rd Sam!
The Final Conflict (1981)
This movie was the 3rd part in the original The Omen series, which tells the story of Damien Thorn, the son of the devil.
Sam Neill plays the title character, Damien, who is now an adult and becomes the Ambassador to Great Britain. The rest of the cast is pretty much a bunch of unknowns that I have never heard of.
I remember going to watch this movie with my parents when I was much younger. I'm not sure why they decided to take me to see this particular movie to be honest.
The Hunt for Red October (1990)
In this film directed by John McTiernan and based on a Tom Clancy novel, Sam plays Captain Vasily Borodin, the Executive Officer of the Russian submarine, the Red October.
Also starring in this film were Sean Connery, Alec Baldwin (who plays Jack Ryan, who was played later by Harrison Ford in Patriot Games and in Clear and Present Danger and then even later in the prequel, The Sum of All Fears by Ben Affleck), Scott Glenn, James Earl Jones, Tim Curry, Fred D Thompson, and Stellan Skarsgard.
Bicentennial Man (1999)
This film was directed by Chris Columbus and also starred Robin Williams and Oliver Platt. In this one Sam plays Andrew's (Robin William's character) "owner."