I don't know.
Some people suggest that without the belief in god there would be no basis for morality and 'good behaviour'. But this is untrue. Knowing that there is or isn't an after-life though faith or lack of has not really changed the way people live. Both sides of that coin seem to live equally good and bad lives irrespective of belief.
So, mmm. Depends on what there is. If it is not as religious people believe then maybe some will give up their faith and therby live a different life. Some would stick to their faith in the face of proof to the contrary and so live the life they have always lived.
Oh, now talking about myself. Again, I don't know

. I think if it was shown to be a heaven as described by christians, with things being as roughly described in the bible then I would probably protest against god if it was omnipotent and not benevolent. But if God was benevolent and not omnipotent then I would give it some slack. Logically to me the christian god can't be both omnipotent and benevolent. If it was shown that the Big G was not as many christians thought and was in fact more inclusive and accepting and was just basically about love I would be like 'haw haw' and carry on as I always had.
If there was Nirvana then I would think cool, but I don't think it would change anything. If there was absolutely nothing then perhaps I would be more bold and live with more abandon. If I was to go to a hell then I would be like 'bugger', time to get drunk! After awhile things would go back to normal. Maybe would make allies to turn hell around after I die.
If we became ghosts then I would put more of a show on when alone at home or in the shower....
Overall I think I would find it a comfort knowing. But I am still me, can't be anything but.