I heard a story about 'Calamity Corner' - the 14th at Royal Portrush.
Basically, an 'American visitor' came into the pro shop, paid his green fee, and then immediately went past the first tee and disappeared into the dunes. On returning to the clubhouse 45 minutes later, the pro asked him what he'd been doing. The American said that he had seen a magazine article with 'the best 18 holes in the world' and he wanted to play them all - he had therefore walked straight to the 14th at RP, played it twice, made a 3 and a 4 and walked off.
Leaving aside the fact that this story may not be entirely true, and that surely he should have paid two green fees, this illustrates what's wrong with these type of rankings. Take the 9th at RCD for example - I have a book of 'The world's greatest holes' which includes this in the best 18. Playing it in isolation would miss the point entirely - its greatness lies in the fact that it is a wonderful climax to an incomparable stretch of golf.