Voldemort is one of the most intelligent and powerful characters in the entire book. He is smart and charismatic enough to get what he wants, when he wants, and from whom he wants it from. He recruits people on a daily basis and does wonders for the Dark wizarding community. Voldemort also happens to be the biggest hypocrite in the book. He pushes to "purify" the wizarding world of Muggle-borns and half-bloods, but he himself is a half-blood. Does this remind you of anybody?
Hitler himself was quite an intelligent and charismatic man back in the days of World War II. He, like Voldemort, recruited people as Nazis everday and did amazing things for the German economy. He got nearly everything he strived for but his problem (besides being a war-mongering dictator) was that he always wanted more. Another interesting parallel between said Hitler and Voldemort is that neither are what they want others to be. Like I said, Voldemort wanted to cleanse the world of Muggle-borns and half-bloods, but he himself was a half-blood. Hitler was one in the same; he wanted an Aryan race- blond hair, blue eyes, definitely not Jewish. Ironically, Hitler was a brown-haired, brown-eyed Jew.
Where I'm trying to get at is that the similarites between the two tyrants shouldn't go unnoticed because, all ideas aside, the resemblance could very well be a clue to whether or not Voldemort survives in the end of book seven.