I don't see this as a "live forever" type of thing.
I also don't buy the whole "download your mind into a computer" idea. I am fairly sure it is a myth created by computer scientists who do not understand neurology and neuroscientists who do not understand computers (and mistakenly think that our mind is, in the slightest, comparable to the computers we use that, basically, add and subtract exclusively). Our brains have more in common with the old analog comparators and edge-detection circuits than they do with digital anything.
I do think, however, that we will develop the ability to prolong the organic body indefinitely and also develop the ability to augment it with various mechanical and computational assists. Of course - extreme injury, disease, and a lack of nourishment could still cause death - it is just that aging could be suspended indefinitely.
Although I question whether or not the human mind would persist that long. Exactly how the mind forms out of the brain is a bit of a mystery. It is also unknown just how the brain stores information and handles compounds experiences into knowledge. Is it possible that, after a hundred years of experiences - the mind would start to break down? After two hundred? How about three?
Would we reach a point where our past simply fades away? Some of the research into hypnosis and other altered states of mind (to include some brain injuries) indicate that the mind stores a lot of hard information in vivid detail (which runs against some of the research into memory alteration - which suggests the details of memories can be altered by remembering them... although I postulate that the 'hard' memory exists and it is merely the inability to retrieve all of the details that cause us to draft new information under social pressures for detailed/dramatic stories - which is then stored as a more recent memory of how to retell the story which is called in the future).
Anyway...
I think many people who don't really understand spirituality falsely attribute a belief in God to a fear of death.
Most spiritualistic ideas deal with the purpose of life. From a purely materialistic standpoint - we are born, eat, grow, reproduce, and die. Why do we reproduce? So that our kids can reproduce before they die.
It's a relatively silly venture, to be honest.
Which is why most people adopt a spiritual view that there is a purpose to life aside from having *** with hot people and eating.
It's a concept that has been struggled over since humans were able to communicate ideas.
In that sense - God is what gives life purpose - not what gives death consequence. Some views are more utilitarian than others - but all place the world as some creation of deistic powers and our role within it is a direct consequence (if not the direct intent) of those powers.
For some - we are things to be lorded over by deities.
For others - we are a sort of shard or seed of that deity meant to grow.
For yet more - we are soldiers for those deities; heroes of some kind of RPG or pawns of an RTS.
When you actually look at most of the spiritual ideas out there - most of them focus on life and how to view one's place in it. Only portions of them really look at death. While death is a very mysterious and even haunting process for many - it is really only a minor focus of spiritual ideas.
All of which would still be quite applicable in a world where people could live indefinitely (barring catastrophic injury, disease, or famine).
