I personally recommend:
The Fountain
It's about death, love, immortality and life. There are 3 timelines one in the 16. century where a conquistador tries to find a mayan sanctum, the source of eternal life. The second one takes place 500 years later where a scientist tries to find a cure for cancer to save his wife. And the last one takes place 500 years from now, a journey through time and place to dying star, where a man tries to get the answers for all his question. The same man is in all 3 timelines and... well, watch it for yourself
. Btw the music is fantastic, it's composed by Clint Mansell check out his work!
Enter The Void
A drug consumer/dealer gets shot in Tokyo and is flying as ghost through the city, the past, the future and the now are getting mixed together. It's very graphic and trippy. It's also a bit too long, but it really is a mindblowing and unique experience.
We Feed The World
An austrian documentary about the shocking truth about the food industry. It was an eyeopener for me.
Moon
A man who works in a station on the moon, that feeds the earth with energy discovers that...well watch it for yourself, it's the best sci-fi movies I've ever seen.
Requiem For A Dream
About four people who become/are addicted to drugs and fuck up their lives. The most shocking movie I've ever seen. This was directed by Darren Aronofsky who also directed The Fountain.
Also check out the work of the Ghibli Studios and the work of Satoshi Kon.
Of course there are alot more movies I love but I'll post them later.
Btw there are some great recommendations already here, but we need more!