Didn't read this whole thread. But I would probably say fear of isolation. We're all so fucking... connected these days. Like being in a small cyber can of sardines. I bet people would be scared if suddenly they couldn't always be in contact with people they know. On the same note, I would say another fear is that of actually getting to know the people you think you know. Seeing how they react in important situations. Also, our generation fears getting old.
...On a more physical, primitive fear, I would say probably powerlessly watching your loved ones tortured or killed. But I think that's a fear that every generation has had. The only difference between us and other generations has really been our technology, so the above paragaph is really the only feasible answer to the question, I guess.