A sad day. But so it goes.
I first read "Slaughterhouse Five" in Ukraine, with a class of my best English students, and I remember trying to map the plot(s) together, and discussing what Vonnegut was trying to communicate in how he was telling the story, in addition to what he was telling. (If you've never read Slaughterhouse Five, I strongly recommend it. But make time for it.) That book affected me tremendously, and is still one of my favorites.
Mr. Vonnegut, I'm sorry to see you go, but I'm glad you were here for a while. Thanks for your spirit and contribution. I hope, in the end, you win.
(A good obit: http://www.time.com/time/arts/article/0,8599,1609650,00.html.)