George Rupp
The highlight of President Rupp's administration was his commitment to make Columbia College and SEAS the "center of the University". Under his tenure, admission rates dropped, the endowment soared, and Columbia was once again spoken of as a great undergraduate institution, instead of a school that catered almost exclusively to graduate and professional interests.
George Rupp remains the most College-friendly Columbia president since Nicholas Murray Butler.
Lee Bollinger, on the other hand is a lot less interested in things like undergraduates education and a lot more interested in things like arts, public health, globalization, neuroscience, sustainable development, and diversity.