I think it's funny that the Wyrd Sisters even "own" that name. They got it from the same place JK Rowling probably did. (MacBeth.) You can't sue over something shakespeare did first. It's about as silly as this:
http://www.penny-arcade.com/view.php...03-09-08&res=l (And Blizzard trying to trademark the word "Diablo" since 1996.)