Like Henry, I'm this late, and like Henry there's nothing I can add that hasn't been said for 9 pages so far.
I owe a great part of who I am as an adult to Gary, I treasure the very few times I traded posts with him here, as I never met him in person. And I am deeply saddened. I think we all send out our deepest condolences to his family, and wish there were better condolences for them, and ourselves, to send and receive.
I hope the designers of 4E do a double-check of the new edition, asking themselves if it has met the bar as the Official current incarnation of the work he began. While he was denied a voice in D&D for these many years, D&D should never, never forget it's father.
We miss you already, Gary.