According to a post on the website of Madhouse (the anime studio behind all of Satoshi Kon's films and Paranoia Agent), Satoshi Kon died of pancreatic cancer. Listed below is Kon's final message, which was posted to his website the day after he passed away:
"May 18 of this year, an unforgettable day.
My wife and I received the following prognosis from a cardiologist at the Musashino Red Cross Hospital:
"The pancreatic cancer is terminal and has metastasized to the bone. You have at most a half year left."
When I conveyed my concerns for Yume-Miru Kikai to Mr. Maruyama, he said, "It's fine. Don't worry, we'll do whatever it takes."
I cried.
I cried aloud.
With feelings of gratitude for all that is good in this world, I put down my pen.
Well, I'll be leaving now."
-Satoshi Kon
Prior to his passing, Kon was working on his latest film, a children's movie called "Yume-Miru Kikai" (known in English as "Dream Machine").
I cannot recommend Tokyo Godfathers enough- that film takes a bunch of street trash and turns it into something beautiful. Also worth watching are the "Magnetic Rose" segment from "Memories" and "Roujin-Z" (which he worked on as key animator).
Off-topic but also worth mentioning, key animator Shojuro Yamauchi passed away today. His wide body of work included films such as "Lupin The Third: Secret of Mamo", "Urusei Yatusura: Beautiful Dreamer", "Grave of the Fireflies" and "Spirited Away".
It's been a dark half-week for anime directors and animators.