Ridley Scott is one of my favorite directors, Alien (1979) and Blade Runner (1982) are basically classics and has aged ridiculously well.

Mulholland Drive (2001) is a perfect movie for me but it contains violence, nudity, extremely mature topics, and horror bits but nonetheless is written and shot amazingly. The cinematography is the best David Lynch has ever done.

If you like weird arthouse stuff I recommend Tie Xi Qu (2002), it's a 9-hour long movie of a guy with a cheap camera filming various parts of a declining Chinese industrial city as the economic policies start shifting from rigid communism to more free markets. It has a very thick smog-filled apocalyptic dystopian atmosphere that you never get tired of. It follows the lives of teens living in a soon-to-be-demolished neighborhood, a father-and son scrapping duo, and the workers of a failing steel factory. It's far more interesting than it sounds.