My reason for this list is quite simple. All these courses play differently from day to day. All can be played with a variety of strategies based on conditions,hole and tee placement. Pine Valley is unique to this list in that the options are minimal but the requirement to hit the shot you choose or else makes it a great test.
No. 1: St. Andrews, St. Andrews, Scotland(No. 4 on Golf Magazine's Top 100 Courses in the World)