OK, I'l start but I'm going to list what I think are the Top 3. In order: Monte Carlo, MGM Grand, Harold's Club. I can't imagine anyone would debate Monte Carlo is not the most famous casino in the world and has been for decades. The MGM Grand is both the largest hotel in the world and the site of one of the most famous fires. (I know they are two different places but because they have/had the same name most people think of it as one entity.) Finally Harold's Club or Bust was a slogan that was promoted around the world. Harold Smith put up billboards everywhere. If I was to go farther and try to do twelve I'm sure some of the old Vegas places would be on my list although they tend to all blend together in the average person's mind: Sahara, Stardust, Dunes maybe. Also a name that would probably get mentioned would be Harrah's although they aren't one casino anymore.