Sir PP,
The par 3s are memorable (maybe not the 3rd so much), but none of them shine like 5-8,15,17, and 18 IMHO.
Sir Sheehy,
My favorite were designed by a handful or architects:
Doak: Ballyneal, Barnbougle, Pac Dunes
C &C: Clear Creek, Sand Hills, Friars Head, Lost Farm
MacKenzie: CPC, Royal Melbourne - West
Morris/Sutherland: Royal Dornoch
Crystal Downs has the pedigree, but I would probably put it a level beneath my absolute favorites. The course enjoys a spectacular setting, some spectacular land forms, and some top-notch architecture. But, it is also a bit schizophrenic. Certainly, 18 holes that occupied nothing but tumbling land such as the stretch from 5-8 could get old eventually (variety is good), but the land for 12 and 16 seemed comparatively stale from the get go. It reminded me of Panmure in that respect - the first and last 4 holes there seem quite tame compared with the exciting middle stretch. Ebb and flow is often an asset, but I just didn't get the sense of sustained excellence that permeates every round I've played at (e.g.) Ballyneal.
That said, I'm knit picking. CD is definitely a special place, and it elicits that feeling in the loins as only such places do.
The clubhouse was pretty empty during my visit, but the course was well occupied. Thus, I didn't really have a chance to sample much of the membership. I definitely got a low-key vibe from the staff, in a good way, compared with the handful of other high-ranked classics I've visited.