An interesting thing to note is that this building was home of the Worker's Compensation Board from 1953 to 1974, athough it is more well known for being the old OPP headquarters from when the WSIB's tenantship ended until 1995.
I would have to disagree with the inclusion of the Spadina line in the list. Spadina is almost always busy due to balanced mix of work/live/play transit riders. A well-used transit line should service more than just the work-home commute.
Robarts Library is beautiful! The more time I spend in it the more I seem to develop a reverence for its beautiful austerity. You want to see ugly? Check out the database for Phase II of it's redevelopment.