While it may be his first, it's not his funniest. He gave up the character because he said a man in his fifties acting like a child would just be 'sad'. A role isn't your greatest if it doesn't age well.
While Mr. Bean is what he's best known for, Blackadder is far funnier than Mr. Bean. He's mean, he's weaselly, he's cowardly, he is comedy GOLD. Really, I'd take any moment from Blackadder Goes Fourth as his best moment.
