According to a recent survey of autographs written by celebrities who are now dead, Hitler's is the highest earner averaging 5,950 dollars.
Marilyn Monroe follows swiftly behind at 4,950 dollars.
In joint third place are President Kennedy and Princess Diana at 3,500 dollars.
You can have mine for a fiver.

http://www.paramountcomedy.com/comedy/facts/index.aspx