He'll never see the end of Farscape. He'll never see the last season of Buffy or Angel (No big loss, some may say... ;)). X-Men 3. No more 12 hour pizza runs to Marco's. ;)
But the one that gets me, is that he'll never play World of WarCraft. He put me to shame when it came to Blizzard fanboyism. John not playing WoW is just...wrong. The universe can not make sense of this occurance. This is like me not drinking coffee anymore.
I take comfort in that the last time I saw John, it was on the happiest day of his life, and I will always carry that memory with me, and that I've long come to understand death, it's place in life, and that he may be gone, but he would want us all to go one. He will be remembered, and his life shall be celebrated.
As for his wife, Stephanie, she's currently in critical condition, last I heard. Her will to live isn't very high right now, understandably, and I sincerely hope she changes her mind about that.