Quite a hard question that – not just because there are so many historical figures, but because I’m terrible at history and don’t know many. 
If I did know many, by the way, I’d just give you a short answer telling you who and why, but – as it happens – I have to sit here and waffle while I make some attempt at coming up with an intelligent-sounding answer.
As a regular visitor (and, very occasionally) to Uncyclopedia (http://uncyclopedia.wikia.com) I must at least mention Oscar Wilde, despite never having read anything that he actually wrote. Although I could justify wanting to meet Hitler like this too. That said, meeting Hitler could prove interesting: you could find out (assuming he allowed you to talk with him, and that you can speak German – which I can’t) what made him tick, and exactly why he did what he did.
Other than that (very unsatisfactory) answer, I haven’t a clue, because, really, I don’t know anything about history and I don’t really want to find out. O_o
Also, hi to anyone reading this on my blog (or Tumblr), since I’m syncing these answers over there now.
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