Well, I believe it really is "all that." I think Gib Papazian said it best about the club - something to the effect that there are ghosts there. There are. I believe it. It just has a "feel" that can't possibly be adequately explained. To me, it's an American version of the feel one gets at St. Andrews Old Course - that is THE home of golf, NGLA is the home of American golf. For anyone with a sense of history, its palpable.
On top of that, the course is incredibly great fun to play, with choices galore; wild/wacky/unbelievable greens; and some of the damndest shots you will ever face.
I put it in the top 3 in the world, which goes for me: Sand Hills, Cypress, NGLA. Obviously that's very arguable, and American-centric, but that's my top 3 and I am sticking to it.
