Movies:
Johnny Mnemonic (http://www.imdb.com/title/tt0113481/):
An awesome cyberpunk movie in the same spirit as Blade Runner.
Blade Runner (http://www.imdb.com/title/tt0083658/):
Basically the first cyberpunk movie in my eyes. Basically created the style that cyberpunk is visualized in modern media. Harrison Ford in the main role hunting down clones. It's cool.
The Chronicles of Riddick (http://www.imdb.com/title/tt0296572/):
One of my favourite sci-fi films of the past decade. Vin Diesel does a great job portraying a ruthless killing machine in a dystopian setting. Quite cool. Has a prequel called Pitch Black (http://www.imdb.com/title/tt0134847/), it's not as good, but if you like Riddick as a character, it's worth watching.
Babylon A.D. (http://www.imdb.com/title/tt0364970/):
See above. (You know, except the part about Pitch Black).
Twelve Monkeys (http://www.imdb.com/title/tt0114746/):
A movie with Bruce Willis trying to change the past and by doing so save 5 billion humans from dying of disease. A good movie by any standard I'd say.
The Fifth Element: (http://www.imdb.com/title/tt0119116/)
A movie with Bruce Willis trying to save the world yet again.
World Invasion: Battle Los Angeles (http://www.imdb.com/title/tt1217613/):
If you ignore the Marine core/USA propaganda, I have to say I thoroughly enjoyed this movie. It was nothing like I expected. It's quite a good movie, way better than your standard world invasion/apocalypse movies. Also, is nearly believable, and the aliens act almost smart which is something you don't often see. It is foremost an action movie, but it's a good action movie and the way the story unfolds in the beginning is fairly well done, I think.
District 9 (http://www.imdb.com/title/tt1136608/):
Apartheid in South Africa. Except this time with crab people and humans. Strongly recommend if you're looking for a slightly different take on the sci-fi genre.
Matrix (http://www.imdb.com/title/tt0133093/):
You guys know it, I know it. Good enough.
TV series:
Battlestar Galactica (http://www.imdb.com/title/tt0407362/):
One of my favourite series of all time. I liked nearly everything about it. My only complaint against it was that I could not play games while watching it, because the story is so intense that missing it annoyed me. Also, the space battles were awesome. They have no fancy energy shield and lazors. They have machine guns, nukes and hull strength. Win.
There's a spin-off called Caprica, and I'm not gonna link to it, because it's shite. Avoid it. There's another spinoff planned called Battlestar Galactica: Blood&Chrome (http://www.imdb.com/title/tt1704292/). I hope it's gonna be awesome.
Stargate SG-1 (http://www.imdb.com/title/tt0118480/):
Yeah yeah. It's light-hearted and funny. You just don't have to take it that seriously. Followed by Stargate: Atlantis (http://www.imdb.com/title/tt0374455/)(is alright, not as good as the original one, but whatever) and Stargate: Universe (http://www.imdb.com/title/tt1286039/)(Was actually fairly good at some points, but it did seem to copy a lot from Battlestar Galactica, which is fine)
Babylon 5 (http://www.imdb.com/title/tt0105946/):
One of the greatest sci-fi TV series around. Grew up watching it. And have rewatched it a few times since.
Also, for kickass Kung-Fu you can watch Hero, Fearless and Red Cliff.