I'm echoing.
My first thought was: 1-18. But that's not really true. Some holes stand out, making frequent reappearances in my mind, five-plus years later (alas!). These are my most frequent Ghosts of Greatness Past:
No. 1. Because I'd never seen a setting quite like it -- and because it was a perfect introduction to the 17 that follow. And possibly because, the first round, after a pretty long drive into the evening and a nearly sleepless night and another pretty long drive in the morning, I hit a perfect tee shot, long and straight.
No. 2. I agree with Ran. The green complex is just a gas. My first round there, I hit a little bump-and-run third that had the biggest break I'd ever seen -- and ended up two or three feet from the hole. I was smitten.
No. 7 (the driveable par-4, right? I'm a little vague on some of the numbers). Pure fun.
No. 9. The tee shot. Manageably heroic -- and what a setting!
No 13 (?). The semi-blind, long-iron par-3 -- just because I love the way it looks, with that flag flapping in the wind.
Nos. 16, 17, 18: If there's a better finishing three anywhere, I can hardly imagine it. Those three holes, it seems to me, require every shot in golf -- in just three holes! Accuracy, length, touch -- it's all there, baby!
If one of those holes makes the most frequent visits to my wandering mind, I guess it'd be 17 -- where, in three rounds, I was probably 7 or 8 over par. Couldn't hit the darned green in all that wind! But what a hole!
Give me a future with only Sand Hills' Nos. 16, 17, and 18, over and over again, and I'd be perfectly content.