Okay - so there won't be a huge celebration or a big cake; and you won't find the date on any calendar. But it's an important day to mark: The 30th anniversary of the day disco died. The last of the great rock songs was released in 1974. Go ahead - ask Marty Forbes and Homer Simpson. The subsequent years for rock music featured follow up records from Skynyrd, and Zeppelin. Queen was kinda cool. Boston was overplayed. Bad Company was just Bad Company, and AC/DC had not quite f