In honor of the end of National Library Week, check out this collection of the Most beautiful Libraries in America. You can even register your vote for your favorites.
Not on the list, but I would have added the Portland (Oregon) Library and the Chicago Public Library's big, new-ish downtown building. I might also have to include the Eudora Welty branch of the Jackson/ Hinds County (Mississippi) public library. Maybe not the most beautiful, but a sentimental favorite.
Related post: Beautiful libraries (be sure to follow the link to the world's most beautiful libraries!)