Georgia Tech in its library renovation will move the vast majority of its books into a combined Emory/Tech Library Service Center off-campus. Very few people use the stacks anymore, particularly at this institute dominated by engineering and computer science.
As a young assistant professor at the University of Chicago in the 90's, I averaged about one trip a day to the joint Math/CS library to track down research papers or old books to find various mathematical definitions and theorems. These days I can access all these papers online and get access to mathematical definitions through Wikipedia and other sites.
I miss seeing the papers near the papers I'm looking for. I remember running across a paper grappling with the union of two complexity classes, which inspired this blog post. In order to prove a theorem about context-free languages, we relied on a characterization buried in a 1966 textbook on the topic. The Chicago library had three copies of that book, so I suppose someone once taught from it, a whole course on Context-Free Languages in the 60's.
I last time tracked down books in the library (at Northwestern) to research the history of P v NP for my book, which will itself likely soon follow the others into these "service centers". I can't remember the last time I went to the library to track down information for research purposes.
There's much to miss about looking up research materials in a library. But I also miss my electric typewriter, my almanac and my World Book encyclopedia collection. Can't stop progress.