Perhaps I worded my thoughts wrong. Dahmer was not awesome as a person in doing what he did, but the way he went about it was interesting (I'll admit he was a twisted fuck).
I agree, those guys really are quite scary people, and I would not want to meet up with them in a dark alley. I think if you do a Wikipedia on Manson, you'll see that there were more murders attributed to his name than the famous ones that everyone knows about. (bernard crowe, Gary Hinman are the only ones that I found)
Also, you mention all those famous people, yet you forget the most famous and brutal one of all... Yahweh. >D