Well I think the prize has to go to the Snow White ride. I went on it for the first time ever on our last trip to WDW. I was shocked by the travelling-carnival quality of the ride and even more surprised that they have not changed this ride when other, better rides have been scrapped.
My second choice is the O Canada movie. Here it is, the main attraction at the Canada pavillion and it is sooo dated. Canada has such beautiful scenery and some pretty interesting history (it's not all about fur trapping, logging and canoeing). Way, way more could be done here.