The relatively new Hennepin County Library in downtown Minneapolis made this list of libraries with the most beautiful facades. (Nevermind that I can't really tell WHO chose these libraries, and nevermind that the facade of a library is not really its most important quality, IMHO.) The design sports an airplane-esque wing that may seem silly but is actually kind of cool, because you can see it suspended over Hennepin Ave. from many blocks down the street. I think that it's great for reminding people that the library is there, since it resides at the edge of downtown. I'm having trouble appreciating the inside of the building, but I haven't spent much time there, so maybe it'll grow on me eventually. It has mostly glass walls and no amount of heat makes up for how cold it looks outside on a gray January day.
This library was designed by Cesar Pelli, who designed my favorite building (post-1930) in downtown Minneapolis. Built in 1989, it was originally the Norwest Bank building and will always be so to me. (Other people now call it the West Fargo Center.) It's deco. Tons of stone and brass and loveliness. At night, it's beautifully lit, though when it first opened, there was a brou-ha-ha about how much energy was wasted to light it all night, so a compromise was struck and it's now dark after a certain hour. I worked in it for a few years and it was as functional as it was beautiful.