We at the Book Council of course love any space that dedicates itself to books and the literary arts, and libraries are easily some of the best examples of those types of spaces. Here are a few lists from around the Internet that feature some of the best libraries around the world (many of which appear on multiple lists because they are so great):
The World's Coolest Libraries as compiled by All That is Interesting.
The World's Most Stunning Libraries as compiled by Fodor's Travel.
The Most Spectacular Libraries in the World as compiled by The Telegraph.
10 Best Libraries in the World as compiled by Fun on the Net.
The Most Spectacular Libraries Around the World as compiled by Architectural Digest.
The 25 Most Beautiful Public Libraries in the World as compiled by Flavorwire.
History's Greatest Libraries (some of which are still standing) as compiled by All That is Interesting.