As Kostelanetz says, Orwell didn't see Soviet totalitarianism firsthand but neither did its supporters in the west. Orwell did see, firsthand, the communists who betrayed the anarchists and republicans in the Spanish Civil War, which resulted in many of them being put to death. None of us alive today will know whether Hitchens leaves a legacy for the intermediate or distant future. I do know that he was practically alone on the left in putting truth ahead of ideology whatever the cost to his reputation. I can't think of anyone else of his prominence who did this; I do know that the absence of others meant he got the full fury of the despicable left while others dithered on the fence in order to not lose credibility. In this respect he gave moral and intellectual encouragement to many others, myself  included. As for his atheism, the same is true. As one of the Four Horsemen, the "new atheists" he is responsible for bringing atheism out of the closet and similarly giving the rest of us the courage to speak out. Snotty irreverence is never rewarded of course, but it is desperately needed in these dire times.