For sci-fi, I recommend Dune, Blade Runner & Blade Runner 2049, Arrival, Interstellar, 2001: A Space Odyssey, The Abyss and Edge of Tomorrow. These are all really acclaimed and well known, but I'll recommend them in case you haven't seen some of them.

As for a personal favorite that isn't sci-fi, but never fails to make me smile, I recommend Midnight Run. An incredible action/comedy/Feel-Good movie that has a lot of heart.