ethereal, those pictures of the downtown YMCA remind me of another building near my home -- one of my favorite buildings in Los Angeles, and relevant to your post because it's a former YWCA. I was surprised to see that one of my favorite blogs, Big Orange Landmarks, did a profile of it and I didn't even know!
Mary Andrews Clark Residence
As Floyd B. Bariscale points out, the building is so large, it's hard to capture in a photograph. So here's the bird's eye view from Bing:
The building has appeared in countless movies, and portrayed a mental hospital in at least two that I know of: "Changeling" starring Angelina Jolie, and "The Ring 2" starring Naomi Watts.
A commenter at B.O.L. even posted the building's old phone number! HU 3-5780