I do love older horror films from directors such as Argento, Cronenberg and Polanski and of course the Candy Man with the genious music score by P.Glass. Also some more recent European films as Haute Tension, Thesis and The Last Horror Movie (but I don't recommed these for sensitive people). In horror films a great film score is essential for the end result.
Science fiction: 2001 A Space Odyssey is no doubt one of the greatest, never got dated. Tarkovski films. Dark Star, Red Planet, The Moon...and of course classics like Hitschiker's Guide To Galaxy and The Starship Troopers

Other great films that come to mind: Requem for a Dream, Silence of the Lambs, Funny Games, Jaws (for my generation the theme tune just became unforgettable), Taxi Driver, Aguirre, Brazil, Tideland, Pulp Fiction, Dog Day Afternoon, Malcom X, Colour Purple, Mo' Better Blues, Round Midnight, Bird...
I usually don't care for comedies much, but who wouldn't love such Monty Python classics as The Wholy Grail and The Life of Brian!
I also like Asian films, such as Audition, The Isle, Samaritan Girl, Yellow Earth, The Scent of Green Papaya...
That's only fiction...I like documentaries as well

Only thing is, I don't get to see new films much anymore... There's no time because I am always practicing piano
