Taking my cue from mouse's list otherwise I'd be here all day reccing.
The Tale of the Princess Kaguya - craft wise, it might be the greatest animated film of all time. Tossup with Akira and The Lion King.
Sorcerer - a bunch of sweaty dudes transport unstable TNT in a big truck. When I think of cinema, I think of this.
While You Were Sleeping - I don't like Christmas movies but I watch this every year (and The Muppet Christmas Carol). God-tier romcom.
Children of Men - What can I say man. Grounded sci-fi that gives me chills and makes me cry every time.
Toy Story - Watched this over and over as a kid. First feature-length CG movie and it still hits.
A Hidden Life - Bring tissues.
The Pink Panther - This is a whole series of slapstick comedy films staring Peter Sellers. I love Steve Martin but his reboots ain't it.
Sound of My Voice - Indie film about infiltrating a cult. Formative for me.
The Hunger - David Bowie is a vampire. What else do you need to know?
Harakiri - Good place to start as any for samurai movies.
That was so hard.