Gosh, the GCA membership does get around...
I'm surprised at so few mentions of Donald Ross/Ross hallmark courses: Pinehurst #2, Seminole, Dornoch.
I'm also surprised, and a little impressed, with the uniformity of a lot of the lists.
Anyway, here's mine, heavily limited by the courses I've actually had a chance to play...
(Five in the world)
1. Muirfield
2. The Old Course
3. Prestwick
4. Riviera
5. Pinehurst #2 (Pre-Open; Tom Doak says it can be fixed, so it makes my list.)
(Five in my backyard)
6. Oakland Hills (South)
7. Franklin Hills
8. University of Michigan GC
9. Arcadia Bluffs
10. Detroit Golf Club (South, not North. Dammit.)