So Stephen Hawking doesn't believe in Heaven.  This is apparently a big deal.   It's not that he is wrong, he is most likely right, though the nature of faith is belief in defiance of any evidence so that doesn't matter, the important question is why anyone cares.
Everyone in the public has heard of Stephen Hawking, he is quite famous, but for what?  I can't find a single thing where he has been correct - it's not like we have experimental evidence for his idea on how black holes emit radiation, we just don't have a better answer, which sounds a lot like religion.  Most recently, he basically gave up and endorsed M-theory, which is a delightfully anthropomorphic hypothesis about fundamental physics but has a number of competitors so it tries to consume them all in a questionable framework.   Hawking is not solving any mysteries any time soon and The Grand Design basically seemed to be phoned in, theoretically.  

When he wrote A Brief History of Time, which is a terrific book, he made a metaphor about a theory of everything, writing "It would be the ultimate triumph of human reason – for then we should know the mind of God."

Did atheists suddenly give up on atheism because he wrote that?   Not at all, so why any of them are rushing to list Hawking as some sort of sage endorsement when he says there is no Heaven is beyond me.    If Hawking came out and endorsed Mitt Romney for U.S. president in 2012, would it change any votes?   

Stephen Hawking is to physics what Stephen Jay Gould was to biology - here is John Maynard Smith, Emeritus Professor at Sussex,  on Gould, by way of reviewing Daniel Dennett’s 1995 book, Darwin’s Dangerous Idea:
 Because of the excellence of his essays, he has come to be seen by non-biologists as the preeminent evolutionary theorist. In contrast, the evolutionary biologists with whom I have discussed his work tend to see him as a man whose ideas are so confused as to be hardly worth bothering with, but as one who should not be publicly criticized because he is at least on our side against the creationists. 
So it goes with Hawking; to many, he doesn't have to be right, he just has to be on the same side.    A paleontologist can't be the preeminent authority on evolutionary biology any more than a well-versed theoretical physicist can be an authority on theology.   

Alex Berezow at RealClearScience says Hawking is arguably as well-known as Einstein and laments that Hawking might be better known in the future for insulting religious people with quotes about fairy tales than his excellent early insights in physics.    I don't agree, Einstein's later career was dismal and he was also cited by the religious and atheists for saying various things for and against religion, but he is best known now for his early work.    Let's hope the same happens with Hawking.

One previous Lucasian Professor of Mathematics at Cambridge said "the Supreme God exists necessarily, and by the same necessity he exists always and everywhere" while another, who   received a Nobel prize in physics,  delved into the supernatural and numerology and was still a member of the Vatican's Pontifical Academy of Sciences along with being a famous scientist.    If some questions were too big for Newton and Dirac to be considered authorities, it is unlikely Hawking can be considered one any time soon.