The prestigious organistation known as the International Federation of Football History and Statistics has judged that Gianluigi Buffon was the best goalkeeper over the period 1987-2011. They ranked goalkeepers from 1-143 through a complex voting system. The top 5 is Buffon, Casillas, Van Der Sar, Schmeichel and Kahn. Not too much too complain about there.
But the rankings do open up the Bonner vs Given debate with Given being ranked 62nd and Bonner 40th. Who was better? Was Bonner just one penalty save and a Wim Jonk howler? If Given's feet weren't freakishly small would he have saved Mendieta's penalty? This ranking system also has Jerzy Dudek and Neville Southall ahead of both of them so maybe it isn't totally accurate.