This is the Council on Tall Buildings and Urban Habitat's (CTBUH) web page that describes the way in which buildings are measured and which buildings are the tallest according to those criteria.
Hopefully this will settle some differences in opinions as to what constitutes the heights of buildings. http://www.ctbuh.org/Resources/Talle...6/Default.aspx
Well I agree that the structural height should be counted to the architectural top but the actual building height should end where the structure seizes to be a building anymore such as the roof.
So there would be a difference between world's tallest building and world's tallest structure, even though that structure maybe a building for most of the way up it.
Spires are cheating. I never thought this until the New York Times Tower's rediculously tall spire making it climb becoming NYC's 3rd tallest building.