I was a little sad when I heard about it, as well as bittersweet while reading The Shepherd's crown. Then I closed the book, curled up in bed and wept myself to sleep.
I've found joy in passing his name on to the next generation.
Have you read Shaking Hands with Death? It's... cathartic.
I knew he was gone when I started reading his books, and still I wept for hours when the realisation fully hit me.
Through Discworld I really felt that he was, somehow, in a way, my friend. And then I finished all the books, remembered he was gone and I mourned him like a dear friend.
I'm reading through Discworld for the first time now. Terry's genius cannot be overstated. Each next book is an absolute revelation (well. Eric was good not maybe not a revelation...). The way the characters grow and become individuals, seemingly with their own real lives. It hurts to know Sir Terry will never be able to tell us more about this fantastical, commentary-laden, hilarious world.