In no particular order (just to be different
):
Blade Runner - atmospheric, beautiful, mournful. Brilliant.
The Fifth Element - Probably the ultimate in guilty filmic pleasures.
Casshern - Fight scenes and visuals that knock The Matrix into a cocked hat.
Ghost in The Shell - Probably the best SF anime ever.
Metropolis - still stunning; Fritz Lang's vision of the future is breathtaking.
Brazil - Terry Gilliam is a genius - and the ending still gives me chills.
The City of Lost Children - Jeunet's masterpiece of oddness.
2001 - visually stunning, surprisingly optimistic vision of the...erm...future.
Invasion of the Body Snatchers - so, so creepy.
A Clockwork Orange - shocking, but brilliant.