Resurrecting or preventing?
The original idea was preventing (as in my John Denver example), but y’all go with whatever you think is right.
I like what I’m reading!
Q
Buddy Holly. He was so young when he died–who knows what stuff he could have done had he lived? Plus if I got to make that plane not crash, I’m assuming I’ll get Richie Valens and the Big Bopper for free!
I wish that something could have been done to beat the prostate cancer that killed Dan Fogelberg in 2007.
Frederic Chopin, if that counts. Would have almost certainly contributed even more beauty to the world!
Stevie Ray Vaughan. He seemed to be going in a musical direction that I wasn’t going to love, but it was his right to explore it. After getting himself clean of drugs and alcohol, it seemed cruel that he would so soon die in a helicopter crash.
I’m tempted to say Cass Elliot, as well.
A clip of Cass and John Denver. Wonderful blending of two great voices.
Jesus. I would have had Jesus live to a ripe old age.
First thought not already mentioned in this thread - Marc Bolan
But, I’m with gaffa. It has to be Kirsty MacColl.
I am probably the only one th feel this way, but my first thought was Steve Irwin. Yes, he lived taking risks, but he was *fun *to watch on TV, and he left behind two small children and a wife that loved him very much. I felt as if I had lost a dear friend when I heard the news of his death.
John F. Kennedy.
'd like to see what would have happened in Vietnam, had he lived.
He was born in 1920, so old age probably would have taken him by now anyway, but I would choose Isaac Asimov.
What the hell…Robert Heinlein. Give him another 15 years, at least. Maybe make it 18, and see if he thought the PS3 was overpriced, too. 
I’d also love to save Mozart, who was just reaching his peak when he died. I suspect his death was preventable, not just some random disease. Another person that played a role in their own death.
I’d also love to get Beethoven to modern medical doctors so that he could live another 25-30 years, perhaps. I’m not sure he could eclipse the 9th symphony, but I’d love to give him a shot.
You are not the only one. First one that came to mind when I read the thread title for me, too. I wept watching his funeral, and recently watching some cheesy tribute to dead celebrities show I wept once more when his segment came on. He did so very much for animals and wildlife conservation efforts, and he did it with such child-like enthusiasm and passion. He seemed like a genuinely good person, and he left such little ones…gah. Hubby and I frequently make comments like, “Steve Irwin? Dead. Steve-O? Still alive.”
After Irwin, I’d probably go with John Ritter and Phil Hartman.
Actually, he was my first thought as well, and I raced down the posts to see if anyone else had chosen him. He took risks, but he loved what he did and he loved life. I actually made my wife sit down before I told her, because I know she would cry.
I’ll put in another vote for Jim Henson, possibly the only celebrity death that put a tear in my eye.
And another for Buddy Holly. If he had lived at least another five years I wonder if the Beatles would have broken through the way they did.
Heath Ledger, for sure, and not just because he was a promising actor. It was tragic for someone that young, with a baby, to die so senselessly.
I came in here to say this. I wonder what music would be like now if Kurt had never died…and I really would have loved to see AIC on tour.
Also, I’m hoping someone out there is preventing George R. R. Martin’s death…
Three of my favorites have been mentioned in this thread: Jim Henson, John Denver, and Steve Irwin.
I picked John Denver, but I also mourned greatly when the other two dudes died.
Is he known not to be well? My brother met him at a convention about a year ago and commented to me that he didn’t look well and he hoped Martin made it to finishing the next book.
Is it ironic or just sad that my brother has since died? 
Anyway, just so I’m not completely off topic, I cast my votes with those who said Douglas Adams and Jim Henson
Ooooh I forgot about DA. I do wish he was still alive.
As much as I love the writings of the still living Terry Pratchett I think Douglas was better.
I think the Arthur Dent stuff had run its course. But I’d like to think that DA could turn his hand to a seperare novel or series of novels and make it/them as brilliant as the three part series in five parts that was THHGTTG