I'd love to have seen the 1978 Never Say Die tour, as that year my favourite band, Black Sabbath took a beating from their support act, Van Halen. Pretty sad how Sabbath got blown away on their 10th year anniversary tour though.
One of the reasons I go to Graspop metal meeting each year is because Maiden closes the show 1/2 of the time, so Í guess it's obvious which band i chose.