I have to put in a plug here for the University of Florida course, which cracks John Garrity's Top 50, but will never appear on any other list. (For what it's worth, the property is not flat.)
The course, originally routed by Donald Ross in 1922 (by mail, I'm fairly sure) was sympathetically restored/renovated by Bobby Weed, reopening in 2001. I played the course dozens of times in its old configuration and more than a dozen times after it reopened, and seeing the new version of the course taught me more about golf course architecture than any other playing experience.
It all comes down to angles:
The original layout featured a mere two dogleg holes. (Part of this was explained by its six par 3s, but it was also forced by space constraints: just 113 acres--a square property--for clubhouse, parking lot, and separate practice areas for the members and the varsity teams.) Weed built four new holes on a part of the property that had previously contained two parallel, straight, par 4.5s (the uphill one was marked as a par 5), back-to-back par 3s, and a bit of forest. Three of the new holes are doglegs, two of which are slightly reverse-cambered.
On all those straight holes, on such a short course (~6700 yards), placement of bunkers and angles of greens is essential. In most cases, UF now presents the player with the classic strategic choices of conservative tee shot/difficult angle of approach or aggressive tee shot/easier angle of approach.
Lastly, the angles on the ground play a role here. Placement of shots on the putting surfaces matters, nowhere more so than on the driveable par-4 17th, with a huge, inviting green so complex that any shot hit on the wrong section is an almost-certain three-putt. Rather than rounded, eroded bunkers, mounds, and hollows around the green, the new version of the course has angular features that will severely penalize the player who misses on the wrong side of many greens, and there is often a thin line between success and failure.
I know that angles, as I've described, are essential to almost every golf course discussed on this website. I think the real lesson worth sharing is that a golf course restored by the right hands can be eye-opening.
* A caveat: more work was done on the greens and bunkers again last year. I have not seen the course since, and I can only hope that the strengths I describe have been retained.