I'd have to say the Education Building. I graduated in 2005 in Engineering. The engineering buildings are occupied 24/7 with people studying so the bathrooms there are disgusting. Our group of "studiers" often studied in the education building because the building was always really clean and empty. There's not a whole lot of after hours studying going on in that building. Also, I would bet that the majority of education majors are female, so that's less males using the bathrooms. That's my reasons for my vote of the Education Building! ;D