I was for one a massive fan of his writing. He will be greatly missed by myself and quite a lot of people I know. For those that know his work especially the Discworld novels the last tweets from his account will make perfect sense:
"AT LAST, SIR TERRY, WE MUST WALK TOGETHER."
Terry took Death's arm and followed him through the doors and on to the black desert under the endless night.
The End.
A sad day indeed. Terry Pratchett was a writer with an uncanny grasp of the lunacies of modern society and will be missed by many.
Those of you who enjoyed his works will no doubt be gladdened to hear that what will now be his final book in the Discworld series is to be published later this year (July or August I think)