There is a GLBT center in the Central Library of San Francisco.  It's clean, quiet, modern, and well-stocked with books and computers.  I'm not saying the LGBT Library of NYC's The Center isn't also well-stocked with books, just not as much.  NYC's LGBT Library is also more antique looking, like with those ceiling-high, old wood shelves you need those ladder-on-wheels to access the higher rows of gay books.

Unfortunately I was with friends at San Francisco, and they don't see reason in flying across the nation just to sit in a library all day reading gay books.  The only book I actually read while briefly visiting the circular center was Steven Petrow's Complete Gay and Lesbian Manners.