I’m not really movie guy, but I would add these myself:

• Monty Python and the Holy Grail and/or Life of Brian - both are timeless classic if you’re into silly British humour
• Pulp Fiction - one of my favourites, virtually every scene is memorable or legendary, good acting and very dark yer still funny
• Apocalypse Now - for some strange reason I like movies about Vietnam war and this one is probably my top one (followed by Jacobs Ladder (very grim) and Platoon)
• Shawshank Redemption - it’s recommended everywhere and I can’t argue with that, great touching movie (same goes for Forrest Gump)
• The Crow (90s one) - one of the best noire/goth atmosphere in movies I’ve seen, great soundtrack too
• Catch XXII (1970) - it’s absurd as it should be, book well made into movie