The oddest thing is I can understand why people are suggesting Hitler. He was one of the evillest men in history, but he must have had something going for him to manage to gain his level of influence. I wouldn't want him at large in modern society so I wouldn't resurrect him, if however I was being offered the chance to meet him, I might take that offer.
I just know someone famous could be a disappointment, so I'm picking a Barry the maintenance bloke from a factory I used to work in and my cat Chaplin. Two individuals who I know would be welcomed back with open arms.